Kerr was born in Rutherglen, South Lanarkshire, and attended Calderglen High School, in East Kilbride. He began his football career as a schoolboy with Motherwell. Spotted playing for the Scotland under-16 team in the televised Victory Shield, he moved to England at the age of 16 to begin a two-year scholarship in Birmingham City's youth academy. Much to his surprise, Kerr was included as defensive cover in the first-team squad for a 2010 pre-season tour to Hong Kong and China. He played in only one of the games, as a 76th-minute substitute for Stephen Carr in the 2–0 win against Chinese Super League team Liaoning Whowin. He signed his first professional contract, of two-and-a-half years, in January 2011. Academy manager Terry Westley described the "tall and gangly" Kerr as having "good awareness on the ball", but said that it was "his change of pace that really convinced us to bring him here", comparing him with England international Matthew Upson at a similar age. His first competitive involvement with the first team came in January 2011, when named on the substitutes' bench for the fourth-round FA Cup tie against Coventry City. He was part of the Birmingham squad for their 2011 pre-season visit to Ireland, and played the second half of the friendly against Cork City. Named in the "B" list for Birmingham's 2011–12 Europa League campaign, he was an unused substitute for the play-off round second leg against CD Nacional. In August 2012, Kerr rejoined Motherwell on a six-month loan after a successful trial. He made his debut as a substitute in a 2–1 win over Kilmarnock in the Scottish Premier League on 18 August. The loan was later extended to last for the season. In April, Birmingham confirmed that his contract would not be renewed when it expired at the end of the season.
Motherwell
On 1 July 2013, after his Birmingham contract expired, Kerr signed a two-year permanent deal with Motherwell. On 31 May 2015, Kerr was involved in an incident in Fir Park following the result of a 3–0, 6–1 on aggregate, victory of Motherwell against Rangers, a match that secured Motherwell's place in the Scottish Premiership. After a clash between players Bilel Mohsni and Lee Erwin, Kerr got involved to defend teammate Erwin. Both teams' managers described the event as both "unacceptable" and "disgraceful". Kerr was released by Motherwell at the end of the 2014–15 season.
Stenhousemuir
Kerr signed for Cowdenbeath in November 2015, where he spent one season before signing for Scottish League One side Stenhousemuir in June 2016. At the end of the 2016–17 season Kerr was released following the club's relegation to Scottish League Two.
