whats the word for a person who does good work?

Do you mean a person who does good work-S? Some one who is kind, generous, charitable.. I am thinking Philanthropist.

"Philanthropy is the act of donating money, goods, services, time and/or effort to support a socially beneficial cause, with a defined objective and with no financial or material reward to the donor. In a more general sense, philanthropy may encompass any altruistic activity intended to promote good or improve human quality of life. One who practices philanthropy may be called a philanthropist. Although such individuals are often rich, people may perform philanthropic acts without possessing great wealth." 1

Perhaps you are thinking of a volunteer. They are always doing good work.

A brown-nose.. lol j/k

A hardworking, valuable employee.

An ace.

hard-working, good work ethic

good-worker-guy

efficent