However, he made only one senior appearance for the team as a substitute for Steve Roberts against Stockport County in the Football League Trophy on 5 November 2003; Wrexham lost the game in a 5–4 defeat.

On 21 November his first goal for the club sealed a 1–0 win in a FA Cup 1st Round replay against Walsall at the Bescot Stadium.

[10] During the January 2009 transfer window, McNulty attracted attention as Stockport looked to bring in money to solve financial difficulties.

[13] After scoring on his debut against Peterborough,[14] McNulty ruptured a kidney during Brighton's 4–0 home defeat to Crewe Alexandra on 28 February 2009, and the injury ruled him out of action for the foreseeable future.

[18] McNulty made his first appearance for Brighton since suffering the horrendous injury in a 2–0 pre-season friendly victory at Scunthorpe United, coming on as a second-half substitute.

After making another 10 competitive appearances since his horrific injury, the last being in the 3–2 defeat to Aston Villa in the FA Cup during January 2010, McNulty was allowed to join Championship side Scunthorpe United on an initial one-month loan to furthermore help his comeback to professional football by manager Gus Poyet.

During July 2010, he re-signed for Scunthorpe on a further six months' loan deal,[20] however after suffering an ankle injury requiring surgery, McNulty returned to Brighton on 5 December 2010.