Stoke City

Whittle was born in Derby and began his career in the Army and was deployed to Germany where he served with the British Army of the Rhine.^[2] Whilst in Germany he played football in an army tournament and was spotted by scouts from Celtic and he joined them along with Gary Holt. After a season at Celtic both joined Lou Macari at Stoke City and Whittle made his professional debut away at Southend United in the 1995–96 season. He played in both of the club's play-off matches against Leicester City at the end of the season as Stoke lost 1–0.^[2] He made 40 appearances in 1996–97 as Stoke finished in a mid-table position of 12th.^[2] In 1997–98 Stoke suffered relegation to the Second Division, however Whittle did manage to win the player of the year award despite playing in just 20 league matches.^[2] Under Brian Little in 1998–99 he played in 15 matches scoring his only goal for Stoke against Reading on 3 October 1998. After falling out with manager Little, Whittle was sold to Hull City in November 1998.^[2]

Hull City

Justin spent six seasons at Hull City and was a firm fans' favourite there.^[3] He was recruited by Warren Joyce in 1998 while City were battling relegation from the Football League and became an integral part of the "Great Escape" team. He left after captaining the promotion-winning 2003–04 side – he was offered a new contract at Hull, but with no guarantee of first-team football he chose to accept an offer from Grimsby Town instead. Due to his cult status at Hull, his departure led to widespread criticism of manager Peter Taylor from the fans. Taylor however delivered a second promotion the following season, but many fans still wished that Whittle had still been there to be a part of this success.

Grimsby Town

Whittle joined Grimsby in time for the start of the 2004–05 season after it became apparent that first team opportunities would be limited at Hull due to an influx of new players and that he would lose the captaincy as a result. After an average first season with Grimsby, Whittle went from strength to strength, and provided a commanding force at the back for his club. His efforts in the 2005–06 season saw the club make an appearance at the Millennium Stadium in the play-offs, and go on an impressive run in the League Cup where the club defeated Derby County and Tottenham Hotspur before making an exit at the hands of Newcastle United. After playing in the heart of defence with many different players at the club it was surprisingly his partnership with Nick Fenton in the 2006–07 season that caught the eyes of the club's supporters.

Despite the club struggling in the league, Whittle was voted "Player of The Season" for his efforts and earned himself a 1-year contract extension. It was apparent from the start of the following season that Whittle was to play a smaller or less important role in the club's affairs. The number 6 shirt he had held since he arrived was stripped of him and he was listed as number 15 in the squad. Fitness and injury worries plagued Whittle and when fit, he was often named as a substitute playing second fiddle to the likes of Nick Fenton, Ryan Bennett and Rob Atkinson. As well as this Whittle was not used in the club's Wembley appearance in the Football League Trophy final in March. In April 2008 it was decided by the club that they would not offer Justin Whittle an extension to his contract and he left on good terms in May after playing some of his best football with the Mariners.^[4]

Harrogate Town

In the summer of 2008 Whittle signed for Conference North side Harrogate Town.^[5] Whittle went on to play in 23 games for Town before being released in March 2009.

North Ferriby United

Whittle signed for North Ferriby United in March 2009, slotting straight into his usual central defensive position. After two years with the Northern Premier League side Whittle retired from playing in football in 2011.