Les Wexner also denied knowing about the late sex offender's crimes or participating in Epstein's abuse of girls and young women.
"I was naive, foolish, and gullible to put any trust in Jeffrey Epstein. He was a con man. And while I was conned, I have done nothing wrong and have nothing to hide," the 88-year-old retired founder of L Brands said in a statement to Congress's House Oversight and Reform Committee released before his interview.
The panel's Democrats had subpoenaed him after the latest Justice Department release of Epstein-related documents revealed new details about Wexner's relationship with the well-connected financier.
Representative Robert Garcia, a California Democrat who sat in on Wednesday's interview, expressed scepticism in comments to reporters gathered near the six-hour proceeding.
"There is no single person that was more involved in providing Jeffrey Epstein with the financial support to commit his crimes than Les Wexner," he said.
In response to allegations by the prominent late Epstein victim Virginia Giuffre, who claimed in court documents that Wexner was among men Epstein trafficked her to, Wexner testified to utter devotion to his wife of 33 years, Abigail.
He said he'd never once been unfaithful "in any way, shape, or form".
"Never. Any suggestion to the contrary is absolutely and entirely false," he said.
Wexner's name appears more than 1000 times in the Epstein files, which does not imply guilt, and Wexner has never been charged with any crimes.
Epstein met Wexner through a business associate about 1986 but it was several years before the businessman turned over management of his vast fortune to the "master manipulator" after he connived to gain his trust.
Epstein had "excellent judgment and unusually high standards", Wexner told Vanity Fair in a 2003 interview, and he was "always a most loyal friend".
On Wednesday, the billionaire said he didn't circulate in Epstein's social circle, but often heard accounts of his encounters with other wealthy people.
Epstein "carefully used his acquaintance with important individuals to curate an aura of legitimacy", Wexner said.
He visited Epstein's infamous island only once, stopping for a few hours one morning with his wife and young children while they were cruising on their boat.
"It is interesting that Mr Wexner has already begun to clarify in his mind that somehow he and Mr Epstein weren't even friends," Garcia told reporters.
"We should be very clear that the two were very close, per reporting. They spent a lot of time together."
In one of the newly released documents, Epstein sent rough notes to himself about Wexner saying, "never ever, did anything without informing les" and "I would never give him up".
Another document, an apparent draft letter to Wexner, said the two "had 'gang stuff' for over 15 years" and were mutually indebted to each other - as Wexner helped make Epstein rich and Epstein helped make Wexner richer.
Wexner's spokesperson said Wexner never received the letter, characterising it as fitting "a pattern of untrue, outlandish, and delusional statements made by Epstein in desperate attempts to perpetuate his lies and justify his misconduct".
Wexner told the congressional representatives that Epstein "lived a double life", presenting himself to his wealthy clients as a financial guru with steady girlfriends while "most carefully and fully" hiding his misdeeds with underage girls.
"He knew that I never would have tolerated his horrible behaviour. Not any of it," he said.
The US Justice Department's newly released records contradict Wexner's claim he severed his relationship with Epstein in 2007.
Wexner emailed Epstein in mid-2008, after he was sentenced to jail time in Florida for soliciting prostitution from a minor.
"Abigail told me the result … all I can say is I feel sorry. You violated your own number 1 rule … always be careful," Wexner wrote. Epstein replied, "no excuse".
