Danny Haynes trialled for the Canaries Under-19 side against Birmingham on 13th March 2004. He was then with the Charlton Athletic Academy. On April 3rd, he played for Ipswich's Under-19s ironically again against Birmingham.

Impressing for the Suffolk side, he was one of nine players inducted into their Academy at the end of April 2004. The others were England Under-16 striker Darryl Knights, left back Stuart Ainsley of Felixstowe, Irish striker Billy Clarke, Irish midfielder Owen Garvan, former Chelsea midfielder Sammy Moore, Scottish international Alan Storrie, former Fulham defender Jack Haverson and Northern Irish centre-back Chris Casement.

Haynes broke into the ipswich first team during the autumn of 2005 and scored his first goal against QPR on 10th December 2005. He has since signed his first professional contract that will keep him at Portman Road until 2008. He was responsible for the controversial winner in the East Anglian derby at Carrow Road on 5th February 2006 when his arm hit the ball, deflected off Gary Doherty and went into the back of the net.

Danny joined League One strugglers Millwall on loan on the 26th September 2006

The People reported on 15th April 2007 that both Liverpool and Everton were monitoring Haynes' progress. After the Everton rumour resurfaced in late September 2007, with Aston Villa also said to be interested, Ipswich extended Haynes' contract until 2010

On 24th May 2008, the News of the World reported Portsmouth were preparing a £2million bid for Haynes

On 29 August 2008, Danny was arrested by Suffolk Police on suspicion of assault related to an incident in the Purdis Farm area of the town

In July 2009, he was linked with transfers to Plymouth or Swansea. Plymouth were rumoured to have offered £1million by The People but this was later downgraded. On 13th July, Danny completed a move to Bristol City fan undisclosed fee rumoured to be around £400,000.

On 20th January 2011, Danny joined Barnsley for an undisclosed fee.

Unwanted by new manager Keith Hill, Haynes was reported to be a summer target for bth Portsmouth, Leicester, Hull and Burnley.

Haynes returned to Charlton, despite interest from Millwall, on 13th January 2012 for an undisclosed fee. He had only played 13 times for Barnsley during the 2011/12 season.