Hackworth signed pro forms with Leeds on 1 August 1998 and was given shirt number 26 in the first-team squad. He regularly featured for the reserves, making substitute and starting appearances, and was rated for his physical presence — standing around 6 ft 1in — and goal threat. Yet breaking into a first team brimming with stars like Alan Smith, Harry Kewell, and Mark Viduka proved beyond reach.

His senior debut finally arrived during the 2000/01 campaign — not in the Premier League but in the club’s UEFA Champions League campaign. On 13 September 2000 he made his first-team debut as a substitute at the Camp Nou in a 4–0 loss to Barcelona, replacing Stephen McPhail in the 68th minute. Shortly afterwards, on 31 October, he made his only senior appearance in domestic cup action: he came off the bench in a League Cup-tie at Tranmere Rovers, only to be substituted himself later in the game.

Hackworth's only other first-team experience came in March 2001, when he featured as a substitute against Lazio at Elland Road in a dramatic 3–3 Champions League draw. That appearance marked his final involvement at senior level for Leeds United. In total, he made just three first-team appearances.

Off the pitch, Hackworth’s Leeds tenure coincided with high-profile legal controversy involving teammates Jonathon Woodgate and Lee Bowyer. Hackworth himself was charged with violent offences in 2000 but was ultimately cleared by Hull Crown Court in March 2001. According to witnesses, he appeared to try to stop the altercation — he looked like actor Chris Klein to a paramedic who spoke to him — and was formally discharged without conviction.

Despite his promise at youth and reserve levels, a serious cruciate ligament injury impeded his progress. In July 2001 Leeds accepted a Ł120,000 offer from Notts County, and Hackworth left Elland Road after five years at the club — with his first-team opportunities effectively behind him.

At Notts County, from July 2001, Hackworth sought playing time but struggled to make a sustained impact. Over three seasons he made 23 starts and numerous substitute appearances, scoring just two goals — once in the Football League Trophy against York City and once in the league against Bournemouth. In total, he made 17 league starts and scored once, adding substitute appearances across league and cups, but didn’t manage to establish himself as a key figure.

In March 2004 he joined Scarborough on loan before signing permanently in the summer. At Scarborough he became a first-team regular, eventually scoring 14 league goals in 75 appearances over two spells. He was released in May 2006 but re-signed two months later and netted nine goals in 39 matches during the 2006/07 season, his most successful campaign as a senior striker.

When Scarborough FC folded in 2007, Hackworth moved into non-league football with Whitby Town, where he quickly became a regular. In November 2007 he joined Harrogate Town in the Conference North, debuting against Alfreton Town and making an impact before returning to Whitby Town as vice-captain. Across these stints, he scored crucial goals and provided leadership before eventually joining Scarborough Athletic in 2011 as captain — scoring twice on his debut in their opening match in August 2011.

Over the course of his non-league career, he scored 37 goals in 123 starts (plus four as a substitute) for Whitby in one spell, and captained Scarborough Athletic as they rebirthed from the ashes of the old club. He retained his involvement in football throughout, both as a player and later taking coaching roles and teaching at Pindar School in Scarborough.

Looking back at his Leeds United phase, Hackworth’s journey reflects the narrow margins for academy-born strikers. Despite shining in the youth and reserve set-ups — including scoring in reserve friendlies such as versus Oldham — he never appeared in the Premier League and only featured in cup and European substitute roles. Competing with future internationals limited his pathway, while injuries and off-field distractions further derailed progress. He remains emblematic of many promising young English forwards at Leeds around the turn of the millennium: talented, professional, but ultimately unable to bridge the gap to the top level.