Chris Waller had American Pharoah eating out of his hand before the Kentucky Derby, an encounter Sydney's premier trainer respectfully dines out on.

Meeting the 2015 Triple Crown winner was a highlight of Waller's trip to Louisville last week, where he also watched American Pharoah's trainer, Bob Baffert, at work.

Waller didn't flinch as the first horse to claim the Triple Crown since Affirmed in 1978 snaffled carrots from his hand - and the feeling was mutual.

"He was such a laid-back horse. When he was winning all those races he was getting mobbed by spectators, the media and never got stressed."

Waller may re-acquaint himself with American Pharoah in the spring when the horse leaves Kentucky's Ashford Stud to stand at Coolmore Stud in the Hunter Valley for a fee of $66,000.

He felt American Pharoah would thrive in Australia because he was not a typically highly strung stallion.

"That's important for their progeny because they have to be able to cope with the pressures of everyday life. I think he'll suit coming down here," Waller said.

American Pharoah retired at the end of the 2015 season after winning nine of 11 starts. He bowed out as the only horse to win America's 'Grand Slam' - the Triple Crown (Kentucky Derby, Preakness Stakes, Belmont Stakes) and the Breeders' Cup Classic.

"It was the the trip of a lifetime," Waller said.

He spent a morning with Baffert, who also trains the world's highest rated horse Arrogate, but was non-committal about whether his methods would change as a result.

"We just went through things. He's got a pretty low-key approach, professional, no frills," Waller said.

"It would be great to get him down here. He'd be great from a marketing aspect, he's an iconic sort of person."