Kennedy was selected for the 2008 summer tour of New Zealand. He was later picked for Martin Johnson's Elite Player Squad on 1 June 2008 ahead of Ben Kay. He started his first game against the Pacific Islanders in which he scored a try.
In 2012 Kennedy was signed for Toulon for the upcoming 2012/13 season In May 2013 he started as Toulon won the 2013 Heineken Cup Final by 16–15 against Clermont Auvergne. Following his request to be released from Toulon, he returned to England to sign for Harlequins for 2013/14 season.
After just one season at Harlequins, Kennedy announced his retirement from playing in May 2014 in order to pursue a coaching career after he was appointed academy director at former club London Irish. On 1 July 2016 he was announced as the new Director of Rugby in a new coaching setup following the departure of Tom Coventry. He left his role on 22 March, 2018 shortly after the appointment of Declan Kidney as technical consultant and Les Kiss as head coach.
