Sheikh Ahmed Zaki Yamani, Saudi Arabia’s long-serving oil minister and the public face of the 1973 oil embargo that punctuated the country’s newfound role as an oil-market superpower, has died. He was 90. Mr. Yamani, who suffered from poor health for years, died in London, Saudi state TV announced Tuesday. He is expected to be buried in his hometown of Mecca, his former colleagues said. His son Hani Yamani said he had died on Monday.

He served in the post for nearly 25 years, starting in 1962. At that time, the U.S.—not Saudi Arabia—dominated the global oil trade as the world’s biggest producer and consumer of the commodity. The Texas Railroad Commission regulated domestic oil prices, while American and British companies held sway over a chunk of overseas production.

When Mr. Yamani took over the oil ministry, Saudi Arabia was a middling producer in the oil-rich Mideast. But Saudi Arabia’s deposits, it turns out, were much bigger than its neighbors’, and soon the country’s output was soaring. Amid a wave of oil field nationalizations across the region, Mr. Yamani led talks to take control of the Saudi Arabia Oil Co., then a joint venture between the predecessors to Exxon Mobil Corp. and Chevron Corp.

At the end of those talks, Aramco was pumping almost 10 million barrels a day, making Saudi Arabia the world’s largest oil exporter. Key to Saudi Arabia’s market dominance was Mr. Yamani’s insistence that Saudi Arabia invest in spare—or unused—production capacity. It was an expensive strategy, but it cemented Riyadh’s ability to quickly ramp up and down output, quickly influencing global prices.

“He was at the very center of the creation of the modern age of oil,” said Daniel Yergin, the Pulitzer-Prize winning author of “The Prize,” a history of the oil industry.

Born in 1930 into a prominent family in the holy city of Mecca, where his father was the head of the religious court, Mr. Yamani was among the first generation of Saudi technocrats sent overseas. He earned a bachelor’s degree in law in Cairo and then set off to New York University’s School of Law, where he received a master’s in comparative jurisprudence.

Then-Crown Prince Faisal, son of the founder of Saudi Arabia King Abdulaziz, took him under his wing upon his return, leading to his appointment as oil minister at the age of 32. As head of what would become the region’s biggest oil player, he would also become the de facto leader of the Organization of the Petroleum Exporting Countries, shaping it into a formidable, global economic force.

Arab members of the group agreed to embargo oil exports to the U.S. in 1973, to protest Washington’s support of Israel in the Yom Kippur war that year. Crude prices quadrupled and American gasoline prices soared, triggering long lines at filling stations across the country and a global economic recession.