Wrack began his career as a trainee at Derby County in 1994 and made his debut for the "Rams" under Roy McFarland in the 1994–95 season.
He was handed his "Mariners" debut by player-manager Brian Laws on 17 August 1996 when he came on as a 78th-minute replacement for Neil Woods in Town's 3–1 home defeat to Wolverhampton Wanderers.
During the same season Wrack also spent a month on loan at Shrewsbury Town, featuring in five games for Fred Davies's "Shrews".
Grimsby earned promotion back to the First Division via the play-offs as well as winning the Football League Trophy in a Wembley double, however, Wrack did not feature in either occasion.
[4] He was voted onto the PFA Team of the Year as the "Saddlers" secured promotion out of the Second Division in the 1998–99 season after finishing in second place behind runaway leaders Fulham.
[8] He scored seven goals from 50 games in the 2002–03 season, and manager Colin Lee praised Wrack's versatility and willingness to play out of position.
He signed a new contract in June 2005, which resulted in a pay cut but guaranteed him a testimonial match; manager Paul Merson said: "this is a real boost to us because when he's fit his name is first on the team sheet".
[16] He marked his return to action with a last-minute goal in a 1–1 draw with Swansea City in a Football League Trophy tie on 17 October 2006.
He was sent off in manager Tim Flowers's first game in charge and the resulting three-game suspension and a series of call-offs due to the weather limited his appearances at Marston Road.
[32] Wrack lost over £500,000 due to a gambling addiction and, in June 2008, received treatment at the Sporting Chance Clinic in Hampshire after becoming suicidal.