He was appointed coach of Widnes Vikings after the club's relegation from Super League in 2005 and the subsequent departure of Frank Endacott.

In his first season with Widnes he led the club to the National League One grand final where they subsequently lost to the Hull Kingston Rovers.

During the 2007 season McCormack won the Northern Rail Cup beating his old side Whitehaven Warriors 56–6 in the final at Blackpool.

In October 2007 Steve McCormack left Widnes and joined the Hull Kingston Rovers as assistant coach to Justin Morgan.

In February 2009 Steve parted company with Widnes and this is thought to have happened after a poor performance against Oldham.