Tim Donnelly began his athletic career in youth sports, and fell in love with competition. Eventually, through hard work and drive, he became a three-sport high school athlete at Decatur High School in Ocean City, Maryland. As a football player, he earned Bayside Conference Player of the Year honors. As a track athlete, Donnelly earned both individual and team conference championships. Donnelly was a standout on the basketball court, as well, leading his team in scoring.
Donnelly continued his football career as a preferred walk-on at the University of Delaware. During his time as a Blue Hen, Donnelly earned a scholarship, became the starter, and garnered multiple awards, including: the Nate Beasley MVP award, CAA Conference Player of the Week, Touchdown Club Player of the Week x3, and Team Unsung Hero. Donnelly still holds the Delaware school record for best single game completion percentage ( .929 min. 12 atts.), and remains in the top 10 in most passing categories.
As a member of the Delaware football team, Donnelly was named to the team-voted leadership council all four years and was also honored as a captain due to his leadership abilities. Multiple times, he was chosen to join Head Coach KC Keeler on the coach's show broadcast on WDSD in Wilmington, Delaware.