Marcus attended Wadham College in Oxford, where he obtained his first class honours undergraduate degree in Mathematics, subsequently going on to complete a DPhil in Mathematics.
One of his first forays into media was the publishing of Prime Numbers Get Hitched where he explained the relation to the Riemann zeta function of the number 42, which is the answer to everything in The Hitchhiker's Guide to the Galaxy series.
Marcus' first appearance fronting a television programme came with the BBC 4 series Mindgames which ran from 2004 to 2005. Under the title The Num8er My5teries, Marcus delivered the 2006 Royal Institution Christmas Lectures; only the third time mathematics was used as the subject.
Following Mindgames, Marcus has appeared in several of the BBC's Horizon series, including Alan and Marcus Go Forth and Multiply and How Long is a Piece of String? both with comedian Alan Davies, followed up by the three-part documentary The Code which was first broadcast in 2011.
Marcus also appears on Dave's School of Hard Sums with Dara Ó Briain where he sets real world mathematical problems for Dara O'Briain and guests.