A president hiring personal assistants/advisors - his budget or the government's?

Suppose that when President-Elect Biden takes office, he decides, “I want to hire someone to be my personal expert on North Korean matters, someone to be an advisor on Iran and the Middle East, and someone to be my consultant on healthcare reform, and someone to be a personal chaplain/spiritual advisor, oh, and a personal fitness trainer to help me stay in shape.”

Does he have to pay such people out of his own pocket, or does the White House have certain allotted budget for people to be hired at the president’s discretion?

The White House has an official budget for assistants to the President. They would be part of the White House Office, which is part of the Executive Office of the President, which has an annual budget of about $700 million. The President has pretty much total freedom to hire whoever they want to for positions within the White House Office, which are pretty much all considered personal staff, not subject to Senate approval or Congressional oversight. There is a practical limit, since the President can only spend as much on the office as a whole as the Congress authorizes, but short of that, the President is free to hire anyone they want at whatever salary they want within the set budget.

Pretty definitive GQ answer. Thanks!

Aren’t there restrictions on the salary of government employees? I don’t think the President can literally pay these employees any salary he wants.

Digging around a little more, you are correct. The President can’t just offer any salary they want.

3 U.S. Code § 107 sets the pay scale for Presidential staff.

So, my initial reply wasn’t quite right. The President can basically hire anyone they want for any position they want, but they have to slot them into an authorized position with an authorized pay scale.

Note that those positions are left deliberately very vague. A President could, I think, hire an Assistant to the President for Personal Physical Fitness (a personal trainer), and pay them at the maximum rate for Level III of the Executive Schedule, if they wanted to, but that would take one of the 6 Domestic Policy Staff positions or 5 Office of Administration positions authorized by 3 U.S. Code § 107.

Edit: I meant, it would take up one of the 6 Domestic Policy Staff positions or 5 Office of Administration positions authorized for Level III pay.

There are some statutory positions within the Executive Office of the President which can’t be changed and do require Senate approval. For example, the Director of National Drug Control Policy. But, as mentioned above, the large majority of EOP positions are essentially discretionary (within limits.)

It’s my understanding that the larger EOP does have statutory positions, but the White House Office, which is sub-division of the EOP, is more or less entirely made up of political appointees that are entirely at the discretion of the President.