Passmore has spent most of his career in the AHL and as a backup goaltender in the NHL. During the 2004–05 NHL lockout he played for the Mannheim Eagles in the German ice hockey league, and in November 2005 he signed with Jokerit in the Finnish SM-liiga to replace Karl Goehring, but was eventually replaced by Tom Askey. In January 2007 he was signed by HCJ Milano Vipers in the Italian Serie A. Passmore is currently the goaltender coach for the Kamloops Blazers.