Buck is a teenager with dark brown eyes, dark brown hair, and light brown-coral skin. He wears a pair of sunglasses, an overly large red button-up shirt with unbuttoned cuffs, a white shirt with a yellow lightning bolt design, dark blue slim-fit jeans, and cyan and blue sneakers with white soles.
Buck is a relaxed and mysterious individual whose favorite activity is hanging out with his friends. He keeps an open mind and appreciates other people's points of view. Much of his behavior mirrors that of Garnet, to the point when he was mistaken to be Garnet by Yellow Pearl until after he showed her his eyes (which was a contrast to Garnet, who has three eyes).
Buck was with the other cool kids: Sour Cream and Jenny Pizza, and offered to give Stevonnie a ride to the RAVE. Out of the Cool Kids, Buck Dewey was the first to figure out that Stevonnie was a Fusion, but didn't bring it up. He later found her being berated by Flint, who he told should let them off easy and allow them to have a good time. He didn't consider the idea too weird or complicated, bringing up a point to Flint that his friend was DJ-ing with DJ-PON3, and that he was more used to such ideas. He managed to convince Flint to let Stevonnie and Lapis Lazuli stay for another hour before bringing them home.
He briefly appears later on in Yellow Tale, at first being mistaken for Garnet by Yellow Pearl. When explained Yellow Pearl's reason to being on Earth, he got her to the Buddwick Public Library. He also appears in Once in a Blue Moon, as one of the affected people in town. Before some of the group could find Starlight Glimmer, Buck Dewey found them, and wondered where Sapphire was. But wasn't convinced with Sapphire's reasoning, believing that Sapphire knew something they didn't, giving a warning for Sapphire's possible "departure".
While not too involved in Season 5, it is revealed that Buck had given a home to Sour Cream's family back at his place, as he had the only main building (aside from Steven Universe) who had a standing house after the Beach City Flooding.
Buck is seen briefly as Spike and the Rutile Twins went to Beach City after everyone was brain-wiped by White Diamond, believing them all to be trouble much like the other residents. He presumably got his memory back after the event.