Inslee played the villain in
D.W. Griffith's debut as a director,
The Adventures of Dollie (1908). He and Griffith were friends as stage actors but did not get along well making movies. On one location shoot Inslee physically threatened the director over a perceived slight; Griffith, who knew how to box, knocked him out cold. This incident was shrugged off, but following a second altercation between the two Inslee was fired by Biograph in 1909. After 1913 he was seen most often in slapstick comedies.