There is a legendary example of this: Jack Dorsey being the CEO of both Twitter and Square simultaneously. Yes, it is possible to hold two jobs. It's even possible to be the CEO of two billion-dollar companies. It's far from easy, but it's possible with an extreme dose of discipline and time management.

I heard Jack personally tell the story of how he managed his time at a fireside chat he did in New York. The closest I can get to an online article that talks about it is this: http://money.cnn.com/2011/11/13/technology/dorsey_techonomy/

Take a look at the way he splits the days of his week into themes. Each of his 6 working days has a purpose.

Monday: Management meetings and "running the company" work
Tuesday: Product development
Wednesday: Marketing, communications and growth
Thursday: Developers and partnerships
Friday: The company and its culture
Saturday: (no work)
Sunday: Big picture strategy

But he then goes next level and splits his time between two companies by alternating mornings and afternoons in each office. The article mentions him working 16 hour days – 8 hrs at each company – but when Jack told the story himself, he said he was splitting mornings and afternoons between the companies.

Monday Morning = Twitter
Monday Afternoon = Square
Tuesday Morning = Square
Tuesday Afternoon = Twitter
Wednesday Morning = Twitter
etc

This might be an approach you can think of taking. It means you make it clear what your schedule is, when you will be working on different aspects of each job, and then be incredibly disciplined about sticking to the schedule so other people can accommodate and work with you.

Before I answer your question let us investigate the history of jobs and how they evolved through the course of history:
1. NYENRODE AT THE TIME OF MATIJS VAN DAM (1763–1824): Matijs lived during a time of significant change. He was the witness of six tumultuous historical stages of governance, including:
• De Republiek van de Zeven Verenigde Nederlanden (1588–1795);
• De Bataafse Republiek (1795–1801)
• Het Bataafs Gemenebest (1801–1806)
• Het Koninkrijk Holland (1806–1810)
• Het Eerste Franse Keizerrijk (1810–1813)
• Het Koninkrijk der Nederlanden (1813/1815–today)
Relatively shortly after the establishment of the Kingdom of the Netherlands, Matijs also experienced a development that we would have called Bexit, when in 1830 Belgium separated from the Kingdom of the Netherlands.
2. THE FIRST INDUSTRIAL REVOLUTION: MECHANIZATION & STEAM POWER: Matijs lived at the beginning of the First Industrial Revolution in Britain (est. 1760–1840), which spread internationally. This period was driven by technology inventions, particularly the steam engine, which improved the way that machines could be operated. A strategic application of the steam engine was the steam locomotive which was invented in 1804. The first railway line opened in the Netherlands in 1839 and the expansion of the railway net was another motor behind industrialization. The mechanization of agriculture resulted in a growth of several new factories for example: sugar factories, potato factories, flour factories, and strawboard factories. Agriculture continued to be the biggest economic sector in the Netherlands during the 19th century. However, the industrialization also fueled the rise of other industries such as the textile industry, machine industry, leather-shoe industry, and the cigar industry, to name a few. And these developments demanded new skill sets from the labourers. A consequence of the First Industrial Revolution in the Netherlands was that handmade crafts businesses could not compete with the products from the factories and closed. Former craft workers (including women and children) tried to find jobs at factories. Thus, the supply of labour exceeded the demand which resulted in exceptionally low wages for long hours of work. And this produced a growing gap between the rich and the poor.
3. THE SECOND INDUSTRIAL REVOLUTION MASS PRODUCTION & ASSEMBLY LINE: The Second Industrial Revolution (1870–1914), also known as the Technological Revolution started in the final third of the 19th century, when new technologies brought mass production and rapid industrialization accompanied by the introduction of assembly lines and electrification. Many more factories were built during the Second Industrial Revolution and new jobs were created for people to work on machines. However, existing work was replaced as well. For example, agriculture machines increasingly replaced the work formerly done by people and animals. Workers in factories experienced a challenging life. They typically worked 10 hours a day, 6 days a week, and the working conditions were often unsafe and most work was drudgery. In the famous movie Modern Times (1936), Charlie Chaplin portrays the manic pace of the factory worker on an assembly line. The film well depicts the employment conditions that were created by the Second Industrial Revolution.
4. THE THIRD INDUSTRIAL REVOLUTION COMPUTER & AUTOMATION: The Third Industrial Revolution (1960–1990) brought mainframe computers (1960), personal computing (1970s and 1980s), and the Internet (1990s). This revolution altered the interaction between individuals and companies. Technological advancement placed pressure on the traditional middle class who worked in transaction jobs. For example, the following jobs declined between 1970–2010 because of automation: general clerks (-37%); bookkeeping jobs (-43%); secretaries (-59%); typists (-80%); and telephone operators (-86%).2 On the other hand, a lot of non-transactional and non-production jobs were created that required complex problem solving skills, significant experience, and specific contextual knowledge, e.g. software developers, computer designers, pc network specialists, printer technicians, and IT consultants.
5. HE FOURTH INDUSTRIAL REVOLUTION CYBER PHYSICAL SYSTEMS: Today, we are at the beginning of the Fourth Industrial Revolution (2012– ), which can be described as the advent of “cyber-physical systems” involving entirely new capabilities for people and machines. A cyber-physical system can be defined as a mechanism controlled or monitored by computer-based algorithms, tightly integrated with internet and its users. This revolution is fuelled by smaller and more powerful sensors, the mobile internet, machine learning, and artificial intelligence. The Fourth Industrial Revolution was the theme of the 2016 World Economic Forum (WEF) in Davos. Professor Klaus Schwab, the founder and executive chairman of the WEF, has published a book on this topic. Some people refer to this revolution as a combination of Industry 4.0 and Smart Services. Others combine the trends of the Third and Fourth Industrial Revolution and continue to call it the Third Industrial Revolution or the Digital Revolution. Schwab (2016) identified three reasons how the Fourth Industrial Revolution is different from the Third Industrial Revolution:
i. Velocity – This revolution is exponential rather than linear.
ii. Breadth and depth – It build on the Third Industrial Revolution and combines multiple technologies that are leading to unprecedented paradigm shifts in the economy, business and society.
iii. System impact – It involves the transformation of entire systems, across and within countries, companies, industries, and society.
The Fourth Industrial Revolution is driven by advancements in technologies that have a significant potential to cause disruption. Over history we have seen that technological breakthroughs are speeding up.
Many of the new technologies are disrupting labour markets. Advancements in technologies and new business models are expected to have a profound impact on existing and future jobs, from job creation to job displacement. This has also happened during the First, Second, and Third Industrial Revolution where jobs were eliminated in one sector (such as agriculture) and new work was created in other sectors such as manufacturing and services. Internationally, jobs are not only threatened by technologies such as robotics, but also by declining demand in many industries along with outsourcing (domestic or international). For example, in 2015 about 2.3 million jobs in the US were outsourced internationally. Some researchers claim that outsourcing can help retain jobs or even create new ones in the country of origin for example jobs with a higher level of complexity.
During the Great Recession (2008–2010) 8,792.000 jobs were lost in the private sector in the US and 8,709.000 new jobs have been gained between 2010 and 2014. However, the middle-and higher income jobs were replaced by low-income jobs. Historically, different economists have been concerned about the impact of technology on the workforce. The economist David Ricardo (1772–1823) commented that the deployment of machinery would have a devastating impact particularly on the labouring class. John Maynard Keynes (1883–1946) predicted widespread technology-driven unemployment “due to our discovery of means of economising the use of labour outrunning the pace at which we can find new uses for labour.” The new generation of technologies which are being deployed in the Fourth Industrial Revolution will have the potential to threaten jobs which previously were not impacted by technologies. A study from Oxford University (2013) predicts that 47% of all jobs in the United States have a 70% probability of disappearing over the next 2 decades.
Other studies (Bowles, 2014) finds the share of jobs that are vulnerable to automation in Europe ranges between 45% to more than 60%, with the Southern European workforce facing the highest exposure to potential automation. Employers in the Netherlands expect that 22% of existing jobs will be automated over the next three decades (ING, 2016). However, Dutch employees are more sombre and anticipate that 37% of jobs will be displaced by 2046. An OECD report is more optimistic and predicts that just 10% of the work in the Netherlands has a high risk of being automated. The OECD researchers claim that the threat from technological advances seems less because they consider the heterogeneity of workers’ tasks within occupations, compared to using the occupation-based approach. A 2015 McKinsey Global Institute study also looked at job activities versus occupations. They concluded that current demonstrated technologies could automate 45% of the activities people are paid to perform and that about 60% of all occupations could see 30% or more of their activities automated. The OECD signals an extremely high chance of automatability of jobs now held by less skilled people and people with lower incomes.
Thus, it can be concluded from the above that one job these days is not enough to meet the needs of a person because jobs have become highly unstable with the introduction of machinery and automation. There are multiple benefits to working two jobs. In addition to an increased income, you will acquire new skills, broaden your social network, and make new work contacts. However, working two jobs also introduces challenges, such as maintaining a healthy lifestyle and having time for friends and family despite working long hours.
A few key points to remember are as follows:
1. Manage your time: Effective time management may be the most important component of successfully working two jobs. To help manage your time, you should:
i. Invest in a day planner: Writing daily tasks in a day planner is essential if you are working two jobs. If your schedule is particularly busy, invest in a day planner that makes provisions for smaller time slots so that you can plan your time in detail. It is advisable to plan your week ahead of time, so you can identify possible conflicts and deal with them proactively.
ii. Simplify everyday tasks: You may need to simplify everyday tasks as much as possible when working two jobs. This may involve replacing your drive to the gym with jogging, cooking and freezing large batches of food over the weekend or preparing simpler meals during the week. For example, you can add ingredients to your slow cooker before leaving home in the morning and come back to a ready-made stew.
iii. Make to-do lists: It is important to reduce your worry about future tasks. Keep a to-do list at each job and check off tasks as you complete them to prevent confusing tasks between jobs or procrastinating because you aren’t organized.
2. Choose the second job carefully: If you have decided to take on a second job, you should think carefully about what kind of job you’re willing to commit to. Consider the following:

i. Money: Many people want to take on a second job because of monetary concerns. If this is your reason, you might be able to monetize your current skills for a second job. For instance, a teacher can offer private lessons, or a journalist can work as a freelance writer. If you apply current skills to a second job, chances are you will earn more than if you start a job with no previous experience.
ii. New skills: Your main motivation in getting a second job may be to learn new skills. If so, choose a second job that fits one of your interests and will help you learn a new skill set that could lead to new opportunities.
iii. Distance: Consider choosing a second job that is in your neighbourhood or close to your day job to prevent costly and time-consuming commuting.

3. Manage your money: When you are earning extra money, aim to spend it wisely. Draw up a budget in which you note extra expenses you are incurring because of your second job, such as commuting costs, extra take-out meals or taxes, and subtract that from your extra income. Apply the balance directly to the debt you are paying off or the financial goals you are working toward. This way, you will both achieve your goals and be able to see your hard work paying off.
4. Take care of yourself and loved ones:
Taking on a second job and maintaining a balanced lifestyle requires discipline. In order to maintain your busy schedule, you need to ensure that you stay healthy.
i. Keep exercising: If your schedule becomes busier, it is important to stay active, if possible. You may need to change your exercise regimen to adapt to your new schedule. Hour-long spinning sessions at the gym three times a week, for instance, may have to be replaced with exercises you can do at home, such as jogging or yoga. In addition to exercising, make small changes where you can, such as taking the stairs instead of the elevator.
ii. Eat healthy: It is important to eat nutritious food, especially if you need to maintain your energy at two jobs over a prolonged period of time. To do so, you will need to plan well. You can cook larger meals and freeze them, opt for quicker cooking methods, take lunch with you and keep healthy snacks like fruit and nuts at both jobs.
iii. Take time off: If possible, take at least one day a week off work to rest your body and mind. If your schedule only allows for a few hours of relaxation a week, switch off your phone and try not to think of work at all during that time. Rejuvenating your mind and body is essential to performing well at both jobs and remaining balanced.
iv. Make time for friends and loved ones: Even if you have a busy schedule, aim to make time for friends and family. In the end, a happy and balanced life involves a strong support network and healthy relationships.
v. Get enough sleep: If you want to be successful at maintaining two jobs, you will need to get enough rest. Although it may be tempting to spend time at night relaxing with a book or Netflix, try to get at least seven hours of sleep a night.
5. Protect your first job: Take care that your quality of work at your main job is of a high standard and that your level of commitment remains the same. It would be counterproductive to get a second job only to allow it to damage your performance and relationships at your first job. Until you decide to change your career or start a job elsewhere, your main job should remain your priority. From a legal perspective, you must read through your employment contract to understand what your rights are regarding a second job. Most companies require that there be no conflict of interest and that you not work for competitors. It may also be prudent to inform your manager of your second job. This way, you do not need to worry about people finding out about your second job and making assumptions, and your manager may even prove helpful.
Besides if you do have any questions give me a call: https://clarity.fm/joy-brotonath