Marsh-Brown graduated through the Fulham Academy to sign professional forms in summer 2009. He was on the bench for a number of Fulham's key knock-out games during their run to the 2010 UEFA Europa League Final, including those against Shakhtar Donetsk and Juventus, but he remained on the bench on each occasion. In November 2010, there were reports that both Tottenham Hotspur and Manchester City were considering making £500,000 offers for the player. In January 2011, Marsh-Brown signed an extension to his contract, keeping him at the club until June 2013. Later that month he joined League One side Milton Keynes Dons on a one-month loan deal. Impressing "the Dons", his loan spell was extended to the end of the season. He made his senior debut on 2 February 2011, replacing Lewis Guy 68 minutes into a 2–1 win at Bristol Rovers. Three days later he got his second start, in a 2–2 draw with Sheffield Wednesday at Hillsborough. On 12 February, he scored his first senior goal, earning "the Dons" a 1–1 draw at home to Brentford. On 30 August 2011, Marsh-Brown signed on loan for Dundee United until mid January 2012, with the option to extend the deal until the end of the 2011–12 season. He joined his Fulham teammate Lauri Dalla Valle at Dundee United, who have links with Fulham via their reserve team coach, ex-United player Billy McKinlay. After only one appearance he returned to Fulham. In November 2011, Marsh-Brown left Fulham by mutual consent.