He played one of two sadistic mountain men in John Boorman's 1972 film Deliverance (with Bill McKinney), and several of his lines became infamous in pop culture.

[1] His mother died at a young age, so he left school and began working a variety of itinerant labor jobs to help support the family, including at an orchard and operating heavy machinery.

After returning home, a friend offered Coward a job as an outlaw gunfighter at the Old West amusement park, Ghost Town in the Sky in Maggie Valley.

While performing at the park with an assortment of acting school students working over their summer break, locals, and professional actors, an accident with a prop pistol resulted in two of his front teeth being knocked out.

[5][6] Coward's performance and physical appearance in Deliverance has provided inspiration for other media, most notably the main character from the Primus video "My Name Is Mud", which also sampled lines from the film.