Nigerian born Kelvin moved to the UK as a youngster and his family adopted South London as their home. Playing upfront or as a midfielder he began his career with Manchester City as a member of their academy system. With quick progress through the ranks made, Kelvin was a part of the 2005-06 FA Youth Cup side that lost in the final against Liverpool. He made his first team début for City two years later and scored his first Premier League goal against Bolton Wanderers soon after in a 4-2 win. Loan moves followed to Rochdale, Leicester City and three separate loan spells to Cardiff City.
Kelvin secured a move to Portsmouth in January 2012 but a hamstring injury, quickly followed by a second administration at Fratton Park brought difficult days. With Portsmouth relegated at the end of that season and, despite his wishes to remain on the South coast, Kelvin joined Barnsley on a one-year deal, leaving Portsmouth due to their financial problems. A change of management at Oakwell though saw him released at the end 2013-14 season and he joined the Shakers on a two-year deal that summer. His first season brought instant success with Kelvin playing a key part in the Shakers promotion to Sky Bet League One in the 2014/15 season. Last season proved to be a frustrating one for Kelvin with injuries severely restricting his appearance tally for the first team.