Basketball and volleyball aren't Stewart's only interests. He plays hockey and lacrosse. He kayaks. He even plays piano.
Stewart has a different prosthetic for each activity.
In basketball, the prosthetic arm has a scoop-like contraption on the end. He can use it to corral the basketball but not hold onto it. Rebounding, as it turns out, was the most difficult skill for the 7-footer to learn.
In volleyball, Stewart wears a prosthetic with a rubbery nub. It helps him better control blocks and passes.
Stewart's biggest challenge in sitting volleyball has nothing to do with his arm.
"I've got a lot of leg," he said.
In this fast-paced sport, mobility is key, and scooting around the floor with a pair of 4-foot legs is a problem for Stewart. His legs make it hard for him to move and react.
He has gotten intertwined with teammates' legs and even opponents' feet under the net.
"I lose track of them," Stewart said of his legs. "I don't even know where they are during games."
"Wherever my legs end up, they end up."
That devil-may-care attitude has served Stewart well. Yes, people have wondered whether he should be playing sports. They have stared at his arm. They have commented about his height.
He knows those awkward and sometimes hurtful moments are out there.
"But at the same time," Stewart said, "I don't care because I have no choice."
He is who he is — a 7-footer with a prosthetic arm — and he is comfortable with that. The self-proclaimed one-armed man figures he has to accept it.
"Unless I just sat in my room all day," he said.
Greg Stewart isn't about to do that.
Blending in just isn't his thing.