At a contractual level, often but not always, there is a clause that requires the Board to approve the compensation of the CEO (but not other employees).
At a practical level, the CEO reports to the board, so the board sets her compensation, much as the CEO sets the compensation of her reports.
In practice …
- if you don’t have a board, the founders do whatever they want
- if you do have a board, you propose an initial comp structure to them, and generally, the board reviews it each year
- as time goes on, all you will care about is your equity stake. It will be up to the Board to think through any additional grants down the road. You can’t unilaterally grant yourself more stock.