The accusation against Josh Harris was part of a late Tuesday night filing in a New York state court in Manhattan, where Black is defending against a lawsuit filed in June by Guzel Ganieva, with whom he had a 6-1/2-year relationship.
Ganieva, a former model, accused Black of rape and other abuse and of defaming her by claiming she tried to extort him. Black has denied her claims, and filed a defamation and racketeering conspiracy lawsuit against her and her law firm.
In Tuesday's filing, Black sought Ganieva's phone records to support his claim that her lawsuit was an "off-shoot" of an "attempted Apollo coup and smear campaign" by Harris to undermine him starting in 2020 after allegations surfaced that Black had paid Epstein financial management fees.
Harris "chafed" because Black was "first among equals as CEO and executive chair," according to the filing, and saw Black's ties to Epstein as "an opportunity to take over at Apollo."
The filing said Harris hired public relations executive Steven Rubenstein to "help seed harmful stories" about Black. He "forged ahead with a malicious campaign" to take Black down after being passed over in January 2021 for the CEO job at the private equity firm.
Black relinquished the CEO role and was replaced by Marc Rowan after a review by the Dechert law firm found Black paid Epstein $158 million for tax and estate planning. He stepped down as Apollo's chairman in March.
Representatives for Harris and Rubenstein said neither man had relationships or dealings with Ganieva. They also denied Black's claims.
"Mr. Harris has nothing whatsoever to do with the deeply troubling situation Mr. Black finds himself in, and any statement or implication otherwise is unhinged at best," a spokesman for Harris said.
Evan Farber, a lawyer for Rubenstein, said Black's claims "offer a concocted, ever-evolving conspiracy theory, packed with false information, that are not based in reality."
Apollo announced Harris' plan to leave his own day-to-day role in May.
Epstein killed himself in August 2019 while awaiting trial on sex trafficking charges.
(Reporting by Jahnavi Nidumolu in Bengaluru and Jonathan Stempel in New York; Additional reporting by Akanksha Khushi and Maria Ponnezhath in Bengaluru; Editing by Noeleen Walder and Cynthia Osterman)
By Jahnavi Nidumolu and Jonathan Stempel