David Schlemko was born on May 7, 1987 in Edmonton, Alberta. A product of the Medicine Hat Tigers of the WHL, he was signed by the Phoenix Coyotes in 2007 and joined the San Antonio Rampage of the AHL before making his NHL debut with the Coyotes in 2008-09.
Schlemko would appear in 3 games for the Coyotes in 2008-09, registering the first point of his NHL career; an assist.
After bouncing around the Coyotes organization for eight seasons, Schlemko was claimed off waivers by the Dallas Stars on January 3, 2015.
He only played five games for the Stars before he was placed on waivers once again and was claimed by the Calgary Flames on March 1, 2015.
As an unrestricted free agent at the end of the 2014-15 season, Schlemko signed a one year contract with the New Jersey Devils. After just one season in New Jersey in which he scored six times and added 13 assists, Schlemko signed a deal with the San Jose Sharks and joined the club for the 2016-17 season.