He signed for Premier League Charlton Athletic in March 1999, and played five games for the Addicks following their relegation into the First Division.

Limited to fourteen league appearances in 2001–02, he was a seventieth-minute substitute for Ben Burgess in the 2002 play-off final, though his team lost the game 2–0 to Stoke City.

Instead his season was most notable for a clash with sixteen-year-old teammate Moses Ashikodi, who reportedly threatened McCammon with a plastic knife.

[4] McCammon went on to make a substitute appearance in the 2004 FA Cup Final, coming on for Neil Harris after 75 minutes, as Millwall lost 3–0 to Manchester United.

[9] The following month he joined League One Bristol City on loan,[10] after Watford manager Aidy Boothroyd showed no interest in signing the striker.

[12] He was not offered a permanent deal with Bristol in the summer,[13] and upon his return to Brighton he found the club relegated out of the Championship.

[18] He was a 71st-minute substitute for Richie Wellens in the 2008 play-off final at Wembley Stadium; Donny beat Leeds United 1–0 to achieve promotion into the Championship.

[20] Recovering from a hamstring injury in pre-season,[21] he posted five goals in 35 games in 2008–09, and was an unused substitute in the club's play-off final victory over Shrewsbury Town.

[24] After returning to Gillingham from Valley Parade he turned down a loan move to Conference South side Dover Athletic.

Challenged to prove his worth in August by manager Andy Hessenthaler,[26] he played just six games of the 2010–11 campaign, at was released after the expiry of his contract.

On 15 June he played for his country in an 8–0 defeat to the United States at The Home Depot Center in Carson, California.