Leon Black has quit his leadership positions at Apollo Global Management, ceding power at the investment firm he co-founded 30 years ago after an outcry over his ties to the late paedophile Jeffrey Epstein.

Jay Clayton, the former US Securities and Exchange Commission chair, will become non-executive chair, a role that Apollo had previously indicated that Black intended to keep.

Apollo co-founder Marc Rowan will take over as chief executive immediately.

Since he was designated Black’s successor in January, Rowan has been stamping his mark on the investment group. Earlier this month Apollo said it would merge with Athene Holding, the insurance company that he helped create in 2009 and which has become Apollo’s biggest client.

The deal creates a heavyweight institution with more than $200bn in assets, which will more closely resemble a national bank than a Wall Street investment partnership.

Black’s departure follows intense scrutiny of his personal business activities, including his employment of Epstein to handle art transactions and give tax advice that the billionaire estimated may have provided as much as $2bn in benefits.

“The relentless public attention and media scrutiny . . . have taken a toll on my health and have caused me to wish to take some time away from the public spotlight,” Black wrote in an email to Apollo staff on Sunday.

The Apollo co-founder paid $158m to Epstein over a five-year period ending in 2017, according to a report by law firm Dechert, which the investment firm made public in January. The report found no evidence that Black was involved in any criminal activity or had any knowledge of allegations that Epstein was running an international sex trafficking ring.

Black’s abrupt departure from Apollo’s leadership underscores how his presence in public life has grown increasingly uneasy, despite expressions of regret for his financial relationship with Epstein and pledges to donate $200m to initiatives that “protect and empower women”.

In February, a UN official told the Financial Times that the Dechert report was “not enough” to remove the company from its pension fund’s “watch list” of investments that require extra scrutiny.

While his grip on his investment empire loosened, Black has shown no sign of stepping away from philanthropic engagements. He is chair of New York’s Museum of Modern Art, and has sometimes lent the museum artworks by Pablo Picasso and Edvard Munch from his personal collection.

Even as he announced his resignation from Apollo’s executive committee on Sunday, Black signalled that his departure might be temporary.

“I will remain Apollo’s single largest shareholder and its biggest supporter,” he wrote to Apollo staff on Sunday, adding: “I hope to return at some point.”