Gillham began his career in the camera department, gaining experience as a camera assistant, focus puller, camera operator and Steadicam operator before moving into cinematography. His early work provided a strong technical foundation and informed his approach to camera movement, lighting and collaboration with directors.
His cinematography credits include the BAFTA-winning series I May Destroy You, for which he photographed all twelve episodes, as well as dramas including Anne, Danny Boy, The Man Who Fell to Earth and A Gentleman in Moscow. His work spans contemporary and period productions, with a focus on character-led storytelling and creating visual styles that support the emotional tone of each project.
Gillham is recognised for a naturalistic approach to lighting and photography, combining technical precision with an emphasis on performance and atmosphere. His background as an operator has influenced his approach to camera movement, allowing him to use handheld and Steadicam techniques to create an intimate connection between audiences and characters.
Throughout his career, Gillham has collaborated with directors, producers and creative teams across a range of genres, contributing to acclaimed television drama productions in the UK and internationally.