Kennedy began his career in the youth system at Crystal Palace. He suffered from homesickness during the 1995–96 season, but slowly earned a regular place in the youth team. Kennedy reached the final of the FA Youth Cup and won the Southern Junior Floodlit Cup with the youth team during the 1996–97 season. He signed his first professional contract in March 1997 and was released at the end of the 1997–98 season, having failed to make a first team appearance. A doublehernia operation kept Kennedy out for three months during the 1998 off-season and hindered his chances of finding a new club for the 1998–99 season.
Kennedy signed for Second Division club Wycombe Wanderers in October 1998. He failed to make a first team appearance for the club and instead played for the reserves. He departed Adams Park in July 1999.
Brentford
Kennedy signed for Second Division club Brentford on a two-year contract on a free transfer in July 1999. He received his first call into the first team squad for a league match versus Cardiff City on 28 September 1999 and made his professional debut when he replaced Andy Scott after 85 minutes of the 2–1 victory. He made regular appearances during January 2000, but his season ended after he suffered a torn cartilage during a 2–0 home defeat by Wigan Athletic on 1 April. He made 10 appearances during the 1999–00 season. Kennedy was injured and out of favour under new manager Ray Lewington during the 2000–01 season and made just two appearances before being released on 20 March 2001. He made just 12 appearances during 18 months at Griffin Park.
Kennedy signed for League of Wales high fliers Barry Town on 29 March 2001 and scored on his debut in a 7–1 win over Llanelli. He made seven appearances and scored one goal in what remained of the 2000–01 season as Barry achieved the League of Wales and Welsh Cup double. The title win saw Barry qualify for the Champions League for the 2001–02 season and Kennedy made his European debut when he replaced Kenny Brown after 76 minutes of a 2–0 first qualifying round win over Shamkir, which saw Barry progress to the second qualifying round 3–0 on aggregate. He made 28 league appearances during the 2001–02 season and won his second double in succession. Kennedy made 29 league appearances and scored one goal on the way to his and Barry's third consecutive double in 2002–03. Financial problems forced the owners of the club to file for administration early in the 2003–04 season and Kennedy departed in September 2003.
Kennedy joined Conference club Forest Green Rovers on 5 September 2003. He made 15 appearances for Forest Green and scored one goal before departing the club on 1 February 2004. Looking back on his time with Rovers, Kennedy said that "it was a long commute and with a close family bereavement, my heart really wasn't in it".
Return to Barry Town
Kennedy returned to ailing Barry Town in 2004 and made 73 league appearances and scored six league goals across his two spells with the Dragons.
Kennedy returned to Ireland in 2004 to sign for hometown club Waterford United for the 2004 season. His made five appearances before his departure in August 2004. Reflecting on his time with the club, he said "my form was mixed and I didn't really settle back home".
