Yes, Hal Jordan was in this movie (replacing John Stewart who was the GL representative on the tangentially related Justice League series), but truth be told, he had the least development and fewest lines of any of the core Leaguers. Still it was nice to see that his evil doppelganger on the Crime Syndicate was one of the baddest of the bad, arguably more menacing than Wonder Woman's true counterpart (if you assume it to be Olympia rather than Superwoman- a Mary Marvel analog). I may be mistaken, but other than Sinestro (or the Penguin in his 5 minutes of fame), Power Ring may be the first evil ring wielder to appear in any superhero show.
Link to Power Ring in action.
#25 - Justice League Unlimited: Initiation - John Stewart's new look
#24 - Batman: The Brave and the Bold: Death Race to Oblivion! - Guy Gardner's Lanternmobile
#23 - Justice League of America: Pilot - Doesn't air
#22 - Justice League Unlimited: The Once and Future Thing: Time Warped - Hal Jordan joins the league
#21 - Legends of the Superheroes - Lantern goes live-action
#20 - Justice League: Crisis on Two Earths - Darker shade of green