Born in Belfast, Northern Ireland, Hamm received his education in England before beginning his directing career with the Royal Shakespeare Company.
He became one of the company's most successful directors during his stay as resident director from 1983 to 1988. Rather than stick to the classics, Hamm focused most of his work on new plays by modern leading playwrights.
His experience at the RSC led him to direct major productions in Europe and in time, he became the artistic director of the Sadler's Wells Theatre Company.
By 1989, Hamm had moved from the stage and directed The Bottom Line for the small screen.
He followed up this documentary with his BAFTA award-winning short film, The Harmfulness of Tobacco (1991). That same year he directed Out of the Blue, which was a TV play about a video director, starring the up-and-coming Catherine Zeta-Jones and Colin Firth.
In 1993, Hamm directed three critically acclaimed feature length television episodes for the Rik Mayall Presents series, including Dancing Queen and Micky Love. After a five year hiatus from sitting behind a camera, Hamm returned to film his first comedy feature film, Martha, Meet Frank, Daniel and Laurence, and Talk of Angels (both 1998), both of which boasted such rising stars as Monica Potter, Joseph Fiennes, Rufus Sewell, Frances McDormand and Penélope Cruz.
He started off the 21st century with a new genre, the horror film The Hole (2001), which won the Special Prize of the Police at the Cognac Festival du Film Policier.