Tim is best friends with his quarterback, Jason Street, whom he has known since he was young. Tim has been described as a character "who has puppy-dog, lady-killing eyes under his scraggly bangs." He is the fullback/running back of the Dillon Panthers with jersey #33.
Tim is depicted as a womanizer and his ex-girlfriends include Tyra Collette and Lyla Garrity, with whom he has an off and on relationship.
Landry reads that week's assigned reading Of Mice and Men out loud to him and it is shown that Tim can comprehend the material better and even scored a B- on his assignment.
Tim and Jason drift apart for a while after Jason discovers that Tim has been sleeping with his girlfriend, Lyla Garrity, to cope with his guilt over Jason's accident. Through all the ups and downs, they remain almost unconditionally supportive of each other and are often seen helping one another out or coming to one another's rescue.
In season 1, Coach Taylor's wife discovers that Tim has been struggling academically and had been asking his schoolmates (especially the rally girls) to do his assignments for him.
He copes with life through casual sex and heavy drinking.
Despite his laissez-faire attitude, he is extremely loyal to his teammates when the occasion demands, as shown when he physically hits an opposition player who verbally provokes his black teammate, Smash Williams, and puts his Panthers career on the line to follow best friend, Jason Street, to Mexico to talk him out of a potentially life-threatening situation.
Of the original main characters with whom he went to school, Tim is the only one who remains in Dillon when the show ended.
Riggins also signs to play football at the fictional San Antonio State University, but after a short period of time, he decides that college is a waste of time for him and moves back to Dillon.
Nevertheless, he admits to differ from his character at least in his relations with the opposite sex; "... Billy was about to go to college on a golf scholarship when their father Walt left and Billy became the sole guardian of his younger brother.
Despite their seemingly immature behavior and Tim's stoic and uncaring facade, the brothers are shown to be caring and loyal to each other in times of crisis.