Kelly played college football for the Miami Hurricanes, earning offensive MVP honors in the 1981 Peach Bowl.

Employing the "K-Gun" offense, known for its no-huddle shotgun formations, Kelly led one of the greatest NFL scoring juggernauts.

As a senior, he led East Brady to the Pennsylvania Class 'A' basketball state quarterfinals, and averaged 23 points and 20 rebounds.

Kelly, who disliked cold weather, listed the Minnesota Vikings, Green Bay Packers, and Buffalo Bills.

'"[9] Although he believed that team owner Ralph Wilson would not bring in the right players to build a championship team,[7] Kelly was initially resigned to playing for the Bills, but while meeting with the team to negotiate his contract three days after the draft, a Bills secretary mistakenly let Bruce Allen, general manager of the rival United States Football League's Chicago Blitz, reach Kelly on the telephone; Allen persuaded Kelly to leave the meeting.

Kelly's USFL records eclipsed those of fellow league quarterbacks Doug Williams and Steve Young.

[14] Led by Kelly, the Houston Gamblers took on the Los Angeles Express and quarterback Steve Young, on February 24, 1985.

Houston raced out to an early lead, but the Express mounted a comeback that led to their being ahead, 33–14 with just under ten minutes left in the game.

The Express thought they had the game won, especially after safety Troy West picked off a Kelly pass and returned it 42 yards for a touchdown.

The Gamblers defense forced a punt, and the offense scored again, this time Kelly found receiver Vince Courville for a 20-yard strike.

Kelly and Reed connected for 65 touchdowns during their career together trailing only the tandems of Peyton Manning and Marvin Harrison (112), Philip Rivers and Antonio Gates (87), Steve Young and Jerry Rice (85), Dan Marino and Mark Clayton (79), Peyton Manning and Reggie Wayne (69), and Drew Brees and Marques Colston (68) for touchdowns by an NFL quarterback and receiver tandem.

[18] Kelly, along with Andre Reed, Bruce Smith, Thurman Thomas, and Scott Norwood, was the subject of the 30 for 30 film—Four Falls of Buffalo.

After sitting out the 1997 season, in 1998 Kelly seriously considered an offer to sign with the Baltimore Ravens who were coached by his former offensive coordinator Ted Marchibroda.

Kelly declined the offer due to family reasons and stayed retired; the Ravens instead opted to trade with the Indianapolis Colts for Jim Harbaugh as the latter team prepared for the Peyton Manning era.

This led to mismatches and defensive communication breakdowns and, in the 1990s, established the Bills as one of the NFL's most successful and dangerous offenses, instrumental in leading Buffalo to four consecutive Super Bowl appearances.

His 81 completions are the fifth most in Super Bowl history behind Tom Brady, Peyton Manning, Kurt Warner, and Joe Montana.

He was enshrined during his first year of eligibility and headlined a class that also featured John Stallworth, Dan Hampton, Dave Casper, and George Allen.

Fellow Hall of Fame member and former head coach Marv Levy was Kelly's presenter at the ceremony.

The Hunter James Kelly Research Institute was founded at the University at Buffalo in 2004, where neuroscientists and clinicians are studying myelin and its diseases.

Chad Kelly played college football at the NCAA Division I level for the Clemson Tigers and the Ole Miss Rebels and took part in the 2017 NFL draft, in which he was selected last overall in the seventh round by the Denver Broncos, earning the title of "Mr.

Casey Kelly, Chad's younger brother, played quarterback for Mallard Creek High School, and graduated in 2019.

[31][32] Casey Kelly also enrolled at Ole Miss, but chose to convert to tight end and play for the team as a walk-on.

Kelly owned and operated Sport City Grill restaurant with the attached Network nightclub on the ground floor of Main Place Tower in Buffalo from 1993 to 1996.

[36][37] On June 3, 2013, Kelly announced that he had been diagnosed with squamous cell carcinoma, a form of cancer, in his upper jaw.

[38] On March 14, 2014, after a follow-up test at the Erie County Medical Center, it was announced that Kelly's cancer had recurred, and that he would begin radiation and chemotherapy treatment.