Hallworth began his career as a trainee at
Ipswich Town before signing a professional contract. During his time at the club he spent time on loan at
Swindon Town,
Bristol Rovers, where he made his professional debut, and
Fulham before returning to become first choice goalkeeper until he was displaced by
Craig Forrest. In 1989, he joined
Oldham Athletic in a deal worth £75,000. He went on to spend the majority of his career at Oldham and was the club's first choice goalkeeper for most of his eight years there. He helped them reach the
FA Cup semi-finals and the
Football League Cup final in his first season, promotion to the
First Division after a 68-year exile in 1991 as
Second Division champions, and to another FA Cup semi-final in 1994. In both FA Cup semi-finals, the Latics held Manchester United to a draw before losing in a replay. He also helped the Latics survive three years in the top flight (
FA Premier League from 1992) before relegation in 1994. He left the club in 1997 to sign for
Cardiff City on a free transfer. He was first choice goalkeeper for three years before being replaced by
Neil Alexander. One of his most notable games at Cardiff occurred in December 1999 away at
Cambridge United; Cardiff had picked up three red cards and were reduced to eight men. Cambridge were awarded a late penalty but Hallworth saved from
Martin Butler to help his side secure an unlikely 0–0 draw. He left Cardiff in 2001 and went on to play for fellow Welsh clubs
Newport County and
Bangor City. At the end of his career, Hallworth part owned the Liverpool based Gentlemen's Club "Rude" with friend and former full time football manager Stewart Holt. ==Honours==