Can the Secret Service order the president?

The Secret Service is an executive agency and thus the President is their ultimate supervisor. He has the authority to order them to do whatever it pleases him to order them to do. read more

But if the President pushes back enough to make it a Presidential edict, brooking no dissent, the Secret Service has to do what they're ordered to do, provided, of course, that the order is lawful (for example, the President cannot tell the Secret Service to randomly kill people solely for the President's amusement). read more

They can't ‘give him an order’ but they can tell him what they require him to do in order for him to remain as safe as possible in the given situation. Of course, a president could overrule what the USSS are telling him to do but it's unlikely, in a field situation, for him to do that as he knows the agents are required to keep him safe. read more

No. There are very few things the President cannot do with the executive branch, but control over the Secret Service like this is not part of it. That said, he can order them to let him go get a bite to eat, but they would get to come with. read more