Undrafted, Schlemko was signed as a free agent on July 19, 2007, by the Coyotes to a three-year entry-level contract and was assigned to the Central Hockey League's Arizona Sundogs.

[5] As a late free-agent addition to the Devils, Schlemko surprised in the 2015–16 season, to solidify his role on the blueline and record a career-high 6 goals and 19 points in 67 games.

Nearing a return from injury, Schlemko played one game on a conditioning stint with AHL affiliate, the Laval Rocket, before suffering a setback in requiring surgery to remove bone fragments in his hand on October 19, 2017.

[11] Schlemko registered 4 points in 8 games for the Rockets before he was traded by the Canadiens with Byron Froese to the Philadelphia Flyers in exchange for Dale Weise and Christian Folin on February 9, 2019.

[12] Schlemko reported directly to AHL affiliate, the Lehigh Valley Phantoms, and played out the remainder of the regular season to appear in 18 games for 4 assists.