Duke, is the codename for First Sergeant, Conrad Hauser, the field commander of the Joe forces. He is second only to Hawk in the G.I. Joe chain of command.
Although, almost unanimously regarded as the main 'good' character of the series there were three characters in the series that had larger vocal parts. Cobra Commander, Lady Jaye, and Flint all had more lines than Duke did in the series. To be fair though, Duke did have over 850 lines in total. He also appeared in 65 episodes of the original series. Duke not only had an implied relationship with Scarlett but Cover Girl also seemed to have a crush on him. We can thank Transformers for the fact that Duke survived the G.I. Joe original animated movie. Duke's planned death was altered to a coma after the outrage that followed the death of former fan favorite, Optimus Prime.
Although absent for most of the first season of the DIC series he would appear, although looking somewhat different, for most of the second season there. In both series he was voiced by veteran voice actor, Michael Bell. For many, this was Michael Bell's biggest role.
He would next appear in Sigma Six, although looking much more like Duke Nukem than the Duke from the original series. Most of his story and personality would remain the same. In this series he was voiced by two different actors. Gregory Abbey, also known as, Frank Frankson, provided his voice in 6 second season episodes while David Wills voiced him in 8 first season episodes.
John Payne would voice the character in the direct-to-video project Spy Troops and Steve Blum would take over the role for the 2009 series G.I. Joe Resolute.
Finally, in the video game based on the live action film, Roger Craig Smith became the 6th voice actor to lend his skills to the role.