Northern Irish striker David Healy joined Norwich on a month's loan from Preston North End on Thursday January 30th 2003. This was two years after he was first linked with the Canaries. Healy began his career at Old Trafford but could not break into Manchester United's first team despite being a Northern Irish international regular. He made just one appearance for United but had a spell at Port Vale where he scored three goals in 16 appearances.

Seeking first team football, Norwich watched him and tabled a bid in December 2000 but this was rejected and the Canaries signed his United teammate Alex Notman instead. Healy stayed in Lancashire and moved to Preston for £1.5million. He scored five goals in his first seven league games and took Preston to the Division One play-offs in 2000/01. Having scored 10 goals in 44 appearances last season reflects his potential but also his loss of form and starting position following David Moyes' defection to Everton and the arrival of Craig Brown as manager.

Healy was signed by Nigel Worthington to halt the goal famine that saw Norwich score just 6 times in their previous 9 league matches. He made his debut against Stoke on February 1st 2003 and scored his first goal for Norwich the following week in the 2-2 draw at Sheffield Wednesday. A regular in the Northern Irish side, he knows his Norwich teammates Phil Mulryne and Paul McVeigh well. Impressed with Healy, Norwich made a bid to sign him on 24th February although Preston boss Craig Brown was adamant that Healy was returning to Deepdale. Although he did return to Preston following the Ipswich match on March 2nd, Norwich and Preston arranged another loan deal on March 13th that would bring Healy back to Carrow Road until the end of the 2002/03 season. He then returned to Deepdale.

According to a report in The Sun on 1st October 2004, Leeds United were seeking to bring David to Elland Road to solve their goalscoring problems. Although Healy was out of contract in the summer of 2005, Preston wanted £400,000 for him. Further bids came from Leeds during October but none of them met Preston's valuation until 29th October when Leeds agreed to pay Preston's asking price which is reported to be around £650,000. After completing a medical, David signed a contract until 2008. Preston chairman Derek Shaw said: "David told both myself and manager Billy Davies that he wanted to leave and felt Leeds were a big club with lots of potential.As soon as he made that clear we had to make sure we got the best deal for Preston"

In August 2005, David was linked with a switch to West Ham with the rumours gaining strength following Leeds' signing of Richard Cresswell from Preston.

On 7th September 2005, David scored the only goal in Northern Ireland's world cup qualifier with England, giving the province their first victory over England since 1972. At the beginning of the following month, he was linked with a £2million switch to Portsmouth. On 18th January 2006, both The Sun and The Daily Express linked David with a switch to West Bromwich Albion with Jason Koumas heading to Leeds in return.

David won his 50th cap for Northern Ireland against Finland on 16th August 2006, scoring against Jussi Jaaskelainen in the Irish side's 2-1 victory - he also captained the team. On 6th September 2006, David hi a hat-trick as Northern Ireland came from behind twice to beat Spain 3-2.

The League Paper suggested on 5th November 2006 that David would be a target for Neil Warnock's Sheffield United during the January Transfer window. The following week, it was suggested he would be joining Watford to replace the injured Marlon King. On 2nd January 2007, the Guardian speculated that "clubs are forming an orderly queue to sign Leeds striker David Healy, with Charlton, Wigan and Sheffield United among those interested." Everton and Sunderland were added to that list at the end of the month but David remained at Leeds. On 11th April 2007, David was linked with a £3m switch to Man City according to the Daily Mirror.

Following Leeds' relegation to League One at the end of the 2006/7 season, David was linked with a return to the Premiership on 13th May 2007 with the News of the World suggesting a re-union with his former Northern Irish coach Lawrie Sanchez at Fulham, whilst The People indicated a move to Middlesbrough. In the end, David signed for Fulham for £1.5milion on 13th July 2007 becoming the fourth Northern Ireland international star to team up again with former international boss Lawrie Sanchez. Aaron Hughes, Steven Davis and Chris Baird also moved to Craven Cottage during the 2007 close season

Healy was honoured by UEFA president Michel Platini ahead of Northern Ireland's friendly clash with Georgia on 26th March 2008. Healy was given an award for scoring a record thirteen goals during the Euro 2008 qualifiers. Healy then went on to score his 34th international goal in the 4-1 win over Georgia but blotted his copy book with an own goal.

Out of favour at Craven Cottage following the appointment of Roy Hodgson who signed Andy Johnson and Bobby Zamora, Healy was linked by the News of the World on 10th August 2008 with a move to Premiership newboys Hull City. The following week saw him linked with Cardiff City and Sunderland. Healy signed for Sunderland for an undisclosed fee on 21 August 2008.

In early January 2008, Healy was linked wth a move to Scottish giants Rangers, possibly as a replacement for Kris Boyd, who had been linked with Birmingham, or for Nacho Novo, who had interested sides in hs native Spain.

David Healy joined Ipswich on loan from Sunderland on 1st February 2010 (Transfer Deadline Day). Healy had been signed for Sunderland in August 2008 by Ipswich's current boss Roy Keane.

On 4th November 2010, Healy was loaned to Doncaster for a month. He scored on his debut, a 2-1 win over Millwall on 6th November, and followed it up with the winner in the 3-2 win at Portsmouth on 13th November.

On 30 January David Healy was allowed to leave Sunderland and join Scottish giants Rangers on a contract until the end of the season. The Northern Ireland international no longer fitted into the plans of Sunderland manager Steve Bruce. Healy, who had a trial with Rangers at the age of 14, replaces Kenny Miller who joined Turkish side Bursaspor.

Out of contract at the end of May 2012, he was linked with a return to England with Football League newboys Fleetwood Town reported to be ready to spend some of the £1m received from Leicester on striker Jamie Vardy, on a proven striker. Crawley Town were also linked as were Scottish sides St Johnstone and Kilmarnock. He signed a 12 month contract with Bury on 23rd August 2012 after Preston decided not to give him a contract.

This signing did not prevent them from being relegated from League One in April 2013. Healy managed to score once in 19 appearances. He was released by Bury at the end of the season who chose not to extend his contract.

On 31 July 2014, Healy played for Glenavon in a 5–0 loss in a pre-season friendly against his former club Leeds United as part of Glenavon's 125th anniversary celebrations.

He became manager of Northern Irish Premier League side Linfield in October 2015 replacing Warren Feeney who left to join Newport County. In the 2016/17 season, Linfield won both the Northern Irish Premiership and the Irish Cup, beating Coleraine 3-0 on 6th May 2017. Linfield won the title again in 2019, securing it with a 0-0 draw against Crusaders on 13th April 2019.

In November 2023 he was linked with the managerial vacancy at League Two Grimsby but dismissed saying "I am surprised, to be honest. I have always said and will continue to say I have a big job here at Linfield. It is a privileged role I am in. I have been loyal for the eight years I have been here in terms of the work and honesty, and success, I have brought here. It came to me as a surprise. I got a few messages last night, and even more so this morning. People reading into whatever it is they are reading into. My concentration is solely on managing Linfield and a big game against Glentoran tonight, and Larne on Saturday."

After Raith Rovers sacked Ian Murray, the Scottish side approached Healy in August 2024 about becoming their next manager. It looked like he was going to sign for Rovers but then changed his mind and extended his contract with Linfield.

In June 2025 Linfield gave Dundee permission to speak to Healy but instead they appointed former Falkirk and Coventry manager Steven Pressley to replace Tony Docherty.