He was portrayed by Jack Lord.
In the film, upon his arrival at Kingston Airport Bond is shadowed by a mysterious man in sunglasses. Bond goes to interview Quarrel at the Kingston docks, but finds the suspicious Cayman Islander to be uncooperative. Persisting with his questions in a local bar, Bond finally persuades his subject to talk in a back storeroom. There, however, the agent is jumped by Quarrel and the bar owner. Bond rapidly subdues them in a brief fight, only to be held at gunpoint by the mystery man from the airport. He reveals himself to be CIA agent Felix Leiter, and that not only are the two agents on the same mission, but Quarrel is helping Leiter. The CIA has traced the mysterious radio jamming of American rockets to the Jamaica vicinity, but aerial photography cannot pinpoint the exact location of its origin. Leiter is Bond's contact who supplies him with information on the case.
James Bond and James Bond Incarnations