Crowley felt he made his challenge too early when riding the regally-bred colt for the first time in the Prince of Wales's Stakes at the Royal meeting in June when third to Highland Reel.
However, Crowley delayed his challenge until much later in the Eclipse and he just got the better of the three-year-old Barney Roy.
"Ulysses has always been held in high regard and it was great it all came to fruition," said the jockey of Sky Bet's 8/1 fourth favourite.
"He's won over a mile and a half, a mile and a quarter, and the way he travels he could probably win over a mile. He's just a very high class horse.
"It was the first time I'd ridden him in the Prince of Wales's and I might have got there a little bit too soon against a horse like Highland Reel, who loves a fight.
"It was always in back of my mind (in the Eclipse) to hold on to him a bit longer."
He will again face another smart three-year-old in John Gosden's Enable, who is a short-price favourite to beat her elders.
Enable will face nine rivals as she bids to win her third Group One of the season.
Gosden's filly was an impressive winner of the Oaks at Epsom and followed up in scintillating style in the Irish equivalent at the Curragh a fortnight ago.
Gosden also runs Jack Hobbs, an easy winner of the Sheema Classic in Dubai before disappointing on fast ground at Royal Ascot in the Prince of Wales's Stakes, while another stablemate, Maverick Wave, is expected to employ pacemaking duties.
Highland Reel has won six times at the highest level and Aidan O'Brien's five-year-old defends his King George crown.
The Ballydoyle handler also saddles Highland Reel's brother Idaho, another Royal Ascot winner in the Hardwicke Stakes.
A third winner from Ascot's big meeting in June taking part is Saeed bin Suroor's Benbatl, who was fifth in the Derby before he claimed the Hampton Court Stakes.
David Simcock runs Eclipse third Desert Encounter, while the in-form Clive Cox is represented by My Dream Boat, fourth in the Grand Prix de Saint-Cloud when last seen.
International interests are catered for by the South American challenger Sixties Song, ridden by Gerald Mosse.
Related Links
Latest Sky Bet King George betting
Comprehensive guide to King George
John Reid reflects upon his win 20 years ago
Mike Cattermole column
