Kellan Lain was born on August 11, 1989 in Oakville, Ontario. The undrafted centre elected to harness his hockey career by playing for the Lake Superior State Lakers in the NCAA. Lain played three seasons with the Lakers where he scored 21 goals and 39 points.
Upon graduating, the Vancouver Canucks signed Lain to a one year contract where they assigned him to their AHL affiliate, the Chicago Wolves. Though not registering a point within his 13 game tryout with the Wolves, the Canucks elected to re-sign him to another one year deal where he would play with their new AHL affiliate, the Utica Comes during the 2013-14 season.
Lain would play 63 games with the Comets where he scored 7 goals and 19 points with 129 penalty minutes. He was rewarded with his solid play by being called up for nine games with the Vancouver Canucks. He scored his first career NHL goal in a 2-1 victory over the Edmonton Oilers on January 21, 2014.
On November 20, 2014, Lain was traded to the Edmonton Oilers for Will Acton where the Oilers sent Lain to their AHL affiliate the Oklahoma City Baron. After not being re-signed by Edmonton, Lain would try out for a number of teams including the Iowa Wild of the AHL on October 25, 2015.