Beesley came to prominence with his first major acting role in The History of Tom Jones, a Foundling, a 1997 television mini-series based on the book of the same name. In 2001, he appeared in the film Glitter, a critical and commercial failure for which he was nominated for a Razzie Award for Worst Supporting Actor. He also appeared in the film Kill Me Later. He starred in the BBC Three medical drama Bodies, which ran from 2004 to 2007. He also starred in the BBC One series Hotel Babylon from 2006 to 2008. He left the show in March 2008, and returned for a guest appearance in one later episode.
Beesley was a member of the jazz band Incognito, but after an eight-month tour with them, decided to end his music career and start acting. On 28 October 2006, Beesley appeared as a special guest Pianist for James Brown during his performance at the Roundhouse in London as part of the BBC's Electric Proms festival.
In June 2007, Beesley starred in the ITV series Talk to Me. He also appeared in the film Red Roses and Petrol, and in the BBC thriller The Last Enemy. In September, Beesley was a guest on ITV's Ant & Dec's Saturday Night Takeaway, where he and Jonathan Wilkes were successful against Ant & Dec in the "Beat the Boys" competition. In October 2008, he appeared in BBC One's remake of the 1970s drama Survivors, as remorseless former Criminal Tom Price. The series consisted of six episodes, with a second series of six episodes transmitted in January 2010. He starred in the ITV drama The Reckoning in April 2011. Beesley gained more exposure with American audiences with a recurring role on Suits and from October 2015 with another recurring role, this time in the popular US Spy Drama Homeland as ex British special forces bodyguard Mike Brown.
Beesley is the narrator for several TV advertisements, including ITV, NFU Mutual's insurance, Energizer's lithium batteries, and PC World. He also provided the voiceover for Manchester United's 2008–2009 season review DVD. In 2011, he appeared in a TV campaign for the UK recruitment company jobsite, and is also featured on their homepage. Beesley narrated the documentary Chatsworth, shown on BBC One in May 2012.
