Oldham-born Molloy had started his career at Warrington in 1988 before signing for Leeds in 1990. At Leeds he won honours for both England (two caps) and Great Britain (he made his debut against France in March 1993). Part of a huge investment to coincide with Rovers return to the top flight, Molloy joined Featherstone for over £100,000 at the same time as Andy Currier (£150,000 from Widnes), Gary H Price (£100,000 from Wakefield), as well as New Zealand imports Iva Ropati and Gavin Hill. In retrospect after four years’ solid service for Featherstone it was probably Molloy who gave the club the best value for money of all those signings.
In his first year under Australian coach Steve Martin, Molloy formed a front-row combination with Richard Gunn and Leo Casey. He did well enough in that debut season to pick up another Great Britain cap versus France. His strong running offered go-forward to the team and he also showed real leadership skills. After another solid year in 1994/95 with Steve coming close to a Wembley final, the super league bombshell dropped and Rovers were demoted. Although the club inevitably suffered the wholesale departure of a large number of their star players, Steve Molloy was one of the few players who decided to stay, alongside Martin Pearson and the returning veteran Deryck Fox. In the centenary season Molloy led the pack manfully, aided by new signings Roy Powell, Jon Sharp and Richard Slater. He was appointed Rovers captain for the first summer season and achieved the almost impossible feat of being selected for the Great Britain tour to New Zealand despite playing outside the top flight. On that tour he won two more GB caps off the bench. It was apparent however that he wouldn’t stay outside super league for the rest of his career and after being unsettled during the 1997 season was determined to move. He was one of the early beneficiaries of the Bosman ruling as applied to rugby league when he moved to Sheffield Eagles. He had played a total of 128 games for Featherstone and scored 23 tries. After Sheffield’s horrific merger, Molloy played a further two years with Huddersfield before moving to Batley, then to his hometown club Oldham in 2003 where he was appointed player coach. On retiring he continued to coach there until he was sacked in 2004.