Someone told him to do something and he did it. "He did what he was told" is also the same.

It means he was obedient.

His mother said "Put on your pants." He did as he was told. He put on his pants. His mother said "Put on your shirt." He did as he was told. He put on his shirt. His mother said "Put on your shoes." He said "No! No! Don't wan't shoes." His mother said "Do as you are told, or I won't let you play outside in the yard." He did as he was told. He put on his shoes.

Also the negative: He didn't do as he was told.

literally （彼は）言われた通りにした。