Chuckles was a wisecracking soldier who couldn't be depended on in a battlefield to follow exact orders. However, he had a knack to be so likeable that it was hard to get angry with him. Hawk saw beyond this and found greater use for him in the field of covert operations.
IDW Comics continuity
Chuckles was a member of G.I. Joe's infantry but was washed out of the program by Hawk though he is considered a very capable agent but "a train wreck of it". His profile shows he would have been more like a mercenary which Hawk would rather have on the Joes' side. To this end, he became the Joes' undercover agent with Jinx as his handler and only contact.
After months spending infiltrating and gathering information from all sorts of terror groups, Chuckles is finally approached by Cobra. A firefight with the Joes wherein he "killed" several of his teammates proved to Cobra they found the right man. Not long after, he is taking assignments from Mr. X, a high-ranking member of Cobra. He also becomes deeply involved with both Jinx and Mr. X's adjunct, Erika Le Tene.
Jinx is captured by Cobra and the situation forces him to kill her in order to maintain his cover. This only made him more determined to get to Cobra's upper echelons and bring down the organization. To this end, he sets off a series of sabotages and manages to reach the office of "Cobra Commander" only to find out he was set up from the very beginning by Xamot and Tomax who are actually Mr. X. The Crimson Twins and Erika escape. With nothing to show for all his efforts and with the death of Jinx hanging over his head, Chuckles goes off the grid for good to pursue his vendetta against Cobra.
Several months passed before the G.I. Joe named Chameleon has tracked Chuckles to a Russian prison. He convinces her to give him a week to prove of Cobra’s whereabouts. He escapes the prison with Max driving his getaway. When Chameleon finds him again, he is already planning a one-man assault on Cobra. Unfortunately, Cobra already knows of what he is planning to do and sends a squad of Vipers to go after him.  His drive and will to go on impresses Cobra Commander who has his wounds treated and welcomes him to Cobra.