Word for a boss who demands the best and also does the best himself

I need a word for a boss/ leader who demands the best and also does the best themself.

Examples:

1. He asks the team to work late until 1am and he does it himself too.
2. He demands that every member of the team meets a ridiculous sales target and he meets it himself and surpasses all.
3. He asks his employees to come to work even if they're ill and it turns out he himself comes to work even though he's severely ill.

The word could be an adjective or a noun.

Not a single word, but depending on your intent, this individual "leads by example" and acts as a "role model".

Even more idiomatically, the boss "practices what he preaches".

I would say such a person was exacting:

[Merriam-Webster]
1 : tryingly or unremittingly severe in making demands
2 : requiring careful attention and precision

// He has very exacting standards.
// he was shocked when his normally exacting supervisor complimented him on a job well done

Note the two senses of the word. The second sense is more task oriented, while the first has a kind of negative connotation to it. Both can apply at the same time. While the first sentence in the question suggests the second sense, the actual example sentences in the question suggest the first sense.