LAS VEGAS — As the referee Joe Cortez lifted Saul Alvarez’s right hand as the winner of his junior-middleweight title bout against Josesito Lopez, Cortez was surprised to have his other hand hoisted in the air by Oscar De La Hoya, a former champion who is now a promoter. Alvarez then placed the champion’s belt around the referee’s waist. In front of a capacity crowd here at MGM Grand Garden Arena, De La Hoya leaned toward Cortez and told him, “You’re the champion.” “It was very touching,” Cortez, 69, said. “I will treasure it forever. When do you see a championship fighter say this to a ref?”

With that Sept. 15 fight, Cortez retired after 35 years as a referee.

Cortez’s career was built on such one-of-a-kind moments. Last year, he became only the seventh referee inducted to the International Boxing Hall of Fame. He has refereed nearly 200 title fights, a record, according to the boxing historian Herb Goldman. In 1993, Cortez was the third man in the ring before the largest outdoor boxing crowd in history, when 136,274 saw the unbeaten Julio César Chávez beat Greg Haugen at Estadio Azteca in Mexico City. He was also the referee in 1994 when George Foreman became the oldest heavyweight champion.

On a recent afternoon, Cortez shared his memories from some of about 3,000 fights he had worked. Answering the door in pressed jeans and a silk shirt, he began with a tour of his rambling house at the northeast edge of the Las Vegas Valley. The gated compound includes a boxing ring, a “wall of fame,” and a movie theater. The ring is surrounded by life-size caricatures of championship fighters and a few enlarged photographs of Cortez’s short-lived boxing career. He and his brother Mike won national Golden Gloves titles, and Joe Cortez had an 18-1 professional record. One room has a wall lined with glass cases displaying gloves he wore in 1960, a bell signed by Muhammad Ali, and photographs of Cortez with Presidents Jimmy Carter, Bill Clinton and George W. Bush. In a pile of photographs yet to be framed, one pictures Mike Tyson folding Cortez into an embrace. The inscription by Tyson says, “I’ll always love you.”

As Cortez talked in a living room dominated by a pool table, the streets of Spanish Harlem, where he was born in 1943, seemed as if they were right outside the door.