Mr. Navab graduated from Columbia University in 1987 and worked at Goldman Sachs before attending Harvard Business School, from which he graduated in 1991. He worked at the investment bank James D. Wolfensohn Inc. before joining KKR in 1993.

By that point, KKR — then formally known as Kohlberg Kravis Roberts — was one of the best-known private equity firms around, having won the battle for R.J.R. Nabisco in 1988, a financial battle immortalized in the book “Barbarians at the Gate.” Today the firm handles roughly $200 billion in assets.

Mr. Navab oversaw numerous leveraged buyouts at KKR, particularly in the media industries, including the takeovers of the Nielsen Company, Yellow Pages and Borden. By 2008 he had become co-leader of the firm’s mainstay North American private equity business. He took sole leadership of the division six years later.

As head of North American buyouts, he helped the firm raise nearly $14 billion for its 12th North American private equity fund, one of the biggest of its kind. He also sat on the firm’s management committee. Executives across the industry believed he was in the running eventually to succeed Mr. Kravis and Mr. Roberts.

But Mr. Navab left KKR in 2017, shortly after it named two other executives co-presidents — most likely the successors to Mr. Kravis and Mr. Roberts.