LOS ANGELES — Barron Hilton, a hotel magnate who expanded his father’s chain and became a founding owner in the American Football League, died Thursday at his Los Angeles home. He was 91.

Hilton’s family said he died of natural causes. He transformed Hilton into the industry’s top brand during his 30 years as its chief executive. The Blackstone Group bought the international chain’s 2,800 hotels — including its famed Waldorf-Astoria — for $26 billion in 2007.

An avid pilot who served as a Navy photographer during World War II, Hilton didn’t begin working for his father’s company until 1951, after he’d made his own fortune in orange juice products, an oil company and an aircraft-leasing business. Hilton also founded the Los Angeles Chargers and oversaw the AFL-NFL merger.

Hilton challenged his father’s will — arguing the foundation’s shares of Conrad Hilton’s fortune that were being used to help Catholic nuns could leave the company open to a hostile takeover — in 10-year legal battle that ended in a settlement.

Hilton was the chairman emeritus of Conrad N. Hilton Foundation. He left about 97 percent of his estate to the foundation, which expects the donation to grow its endowment from $2.9 billion to $6.3 billion.