Prowse is most famous for playing the role of Darth Vader in the original trilogy, although Vader was dubbed by James Earl Jones. Prowse claimed that he had prepared his lines to a professional standard and did not realize until the premiere that his voice would never be heard in the film series. This annoyed him greatly, but he found ways to turn his situation into a point of levity. In later productions, he would deliver joke versions of his lines during filming. George Lucas claimed that he never intended to use Prowse's voice in the trilogy.

During the making of , and it was only revealed to Mark Hamill moments before the specific scene was filmed. However, as David Prowse's lines would be dubbed over anyway, it was apparently decided not to inform him of the dialogue. Once again, Prowse reportedly discovered this major element of his character upon viewing the film's premiere.

Prowse is said to have lobbied to be included in , reprising his role as the fully-armoured Darth Vader, but his requests fell on deaf ears. There is anecdotal evidence from statements made by Hayden Christensen that he (Christensen) had to convince Lucas to use him instead of an anonymous actor. Perhaps partly in response to this, Prowse has developed the habit of signing his autographs "David Prowse IS Darth Vader".

Prowse continues to associate himself with his role in the films and is involved in the convention circuit. Despite this, he has not been included in recent reunions of the original cast, such as those for the 2004 DVD documentary "Empire of Dreams" and the 2005

Within the United Kingdom, Prowse is also well-known as the Green Cross Code Man, as a result of his association with the Green Cross Code road safety campaign for children which ran between 1976 and 1990 and for which he received the MBE in 2000.

He had a role as a

Prowse is married with three children. He helped train Christopher Reeve for the role of Superman. He is also a notable graduate of Bristol Grammar School. He is now the official leader of the 501st Legion, a fan group dedicated to Star Wars costuming.

In 1999, thieves broke in Prowse's home and stole the lightsaber prop he used in the