Shephard was educated at Chigwell School, an independent school in the civil parish of Chigwell in the Epping Forest area of Essex, followed by the University of Birmingham, where he achieved a 2:1 BA Hons degree in Dance, Drama & Theatre Arts. Shepard played Rugby at Woodford Rugby Football Club. A West Ham United supporter, he has also received honours in both rugby and football.
Shephard's career took off in 1998, when he began hosting Channel 4 spin-off show The Bigger Breakfast, alongside fellow presenters including Josie D'Arby, Melanie Sykes and Dermot O'Leary. That same year, Shephard became the first presenter of T4's teen strand on Channel 4, which launched on 25 October 1998. He also presented Control Freaks for the channel in 1998.
Between 2004 and 2006, Shephard presented the first three series of ITV2 spin-off programme The Xtra Factor, whilst Kate Thornton hosted the main show on ITV While hosting the show, Shephard also starred in The Xtra Factor – Battle of the Stars. He left the show after three series after missing out on the main presenting role (which went to Dermot O'Leary after the departure of original host Kate Thornton); he was replaced by Fearne Cotton.