John Smallcombe started his career at the age of 17 as a tea-boy in London at Hemdale Film Company. He quickly transitioned into physical film production, working as a runner and then as an assistant director. Throughout his career, he collaborated with luminaries such as Fred Zinnemann, Michael Apted, Hugh Hudson, Richard Lester, and Ken Russell. His credits include "Lucky Lady," "Tommy," "Mahler," "Chariots of Fire," and "Triple Echo."

In 2000, John moved to Los Angeles to work with multi-Oscar-winning producer John Daly on notable films like "Terminator," "Platoon," "Salvador," and "The Last Emperor." He also co-produced "Love at First Kill" (2008), "The Hessen Conspiracy" (2009), and "Meant to Be" (2010).

In 2021, John produced "Ernest Hemingway’s Across the River and Into the Trees," followed by "Retreat: A Spiritual Journey with Malcolm Schwartzman." He is currently based in London with multiple films in various stages of development, including "Mister Wednesday."