Gann was born in Stillwater, Oklahoma and played scholastically at Lakewood High School in Colorado.

[1] He played college football for the Notre Dame Fighting Irish,[2] where, as a senior, he was honored by United Press International as a second-team All-American.

[3] Gann was selected by the Falcons in the second round of the 1985 NFL draft,[4] and spent his entire career with them.

He started 117 of the 118 games in which he played, recording 23.5 sacks, 1 interception, and 11 fumble recoveries.

[5] He scored a touchdown as a rookie on a lateral from teammate Rick Bryan in a win over New Orleans.