After a stellar career in the Western Hockey League with the Brandon Wheat Kings and Portland Winter Hawks, Agnew turned pro and signed with the Canucks in 1986.

While playing for the Canucks in March 1990, Agnew seriously injured his left knee and required surgery.

He spent virtually the entire 1990–91 and 1991–92 seasons on the Canuck roster as a utility player seeing action at both forward and defence, but was limited to just 44 games over that stretch due to injury and failed to record a point.

Agnew appeared in 81 NHL games over parts of six seasons, recording 1 assist and 257 penalty minutes.

After his playing days were over, Agnew moved to Missoula, Montana, became a United States citizen, and found work as a law enforcement officer.