He had a variety of roles in film, television and theatre including as Red X-Wing Squadron Leader Garven Dreis in Star Wars Episode IV: A New Hope.

These included episodes of Z-Cars, UFO, The Avengers and Randall and Hopkirk (Deceased) and a three-week run of Henry V in 1968 in which he played the lead role.

Director George Lucas disagreed with this so they compromised so that Red Leader would at first be formal but as the battle progressed become more excited.

[4] The performance was Henley's final one on film, as he was diagnosed with bipolar disorder, then known as manic depression, shortly after completing his part and retired from acting.

[4][5][6] When the Special Edition cut of Star Wars Episode IV: A New Hope was released in 1997 it featured an additional scene of Henley in which he talked with Luke Skywalker (Mark Hamill) and Biggs Darklighter (Garrick Hagon).