In 1990 Agnew took over the head coaching job of the London Knights of the Ontario Hockey League.

In 1994–95 Agnew took over the coaching job of the Kingston Frontenacs and led them to their first division title in 1994–95.

Agnew led the team in that evening's game, with Hitchcock set to take over the following day.

[1] On June 15, 2012, the St. Louis Blues announced Agnew had been hired as an assistant coach, under the direction of Ken Hitchcock.

[6] He retained the associate coaching position with organization when the affiliate relocated as the Abbotsford Canucks in 2021.