He played junior hockey with the Regina Falcons in 1925-26 and 1926-27. After that season he went on an odyssey throughout North America until his big break in 1937. During the 1937 Stanley Cup playoffs regular goaltender Normie Smith was injured. Robertson was called on play 6 games in the playoffs. Earl was in net the day Detroit Red Wings won the Stanley Cup in 1937. His name was engraved on the cup for helping Detroit win their third championship. After that Robertson was traded to the New York Americans. He played with them until they folded in 1942 when he retired.