Acclaimed singer Robert Merrill, the opera baritone who felt equally comfortable at opening night in the Metropolitan Opera House or opening day at Yankee Stadium, has died. He was 85.

Merrill died on Saturday at his home in New Rochelle, family friend Barry Tucker said yesterday.

Mr. Tucker said his father, tenor Richard Tucker, and Merrill had performed together around the country. “My father felt that he had the greatest natural voice that America created,” Mr. Tucker said. “He was the best baritone of the day.”

Merrill, once described in Time magazine as “one of the Met’s best baritones,” became as well known to New York Yankees fans for his season-opening rendition of “The Star Spangled Banner,” a tradition that began in 1969.

In his 31 consecutive seasons with the Metropolitan Opera, Merrill performed virtually every baritone role in the operatic repertoire.

He earned admiration for his interpretations of dozens of roles, including Escamillo in “Carmen” and Figaro in “The Barber of Seville,” reportedly his favorite opera.

Merrill once said opera” is the toughest art of all.”

“It’s a human instrument,” he said. “Your voice, so many words, so much music. …There’s a lot of emotion.”

Merrill was known for a velvet smooth voice. Critics wrote that Merrill “worked hard to polish his natural rich baritone” and that he “noticeably improved each season.”

Merrill retired from the Met in 1976 but returned to its stage in 1983, when the company marked its centennial.

“Few leading singers have graced the company with so many performances,” Opera News said in 1996. “None have served it with more honor.”

Throughout his career, Merrill sang with popular stars ranging from Frank Sinatra to Louis Armstrong, appeared worldwide at music festivals and made numerous recordings. Merrill performed as a soloist with many of the world’s great conductors, including Leonard Bernstein; he also made appearances for several presidents, including Franklin Roosevelt, Harry Truman, Dwight Eisenhower, and John Kennedy.

He also was a well-established radio and television soloist, beginning his television career on NBC’s “Saturday Night Revue” in 1949.

Merrill’s lifelong enthusiasm for baseball led to his long tenure at Yankee Stadium, where he sang the national anthem on opening day for three decades.

Merrill was a longtime “friend, Yankees fan and close associate of the Yankees, and we dearly miss him,” team spokesman Howard Rubenstein said. “He sang the national anthem at

Yankee Stadium for many years and provided a true inspiration for us, the ballplayers and all of our fans,” Mr. Rubenstein said.

Merrill, who often appeared in a pinstriped shirt and tattered Yankees necktie, performed the same duty for the Yankees during the World Series, the playoffs and at Old-timers Day.

He took the job seriously and once said he did not appreciate when singers tried to ad lib with “distortions.”

“When you do the anthem, there’s a legitimacy to it,” Merrill told Newsday in 2000. “I’m bothered by these different interpretations of it.”

Merrill made his operatic debut in 1944, singing Amonasro in “Aida” on a Trenton, N.J., stage. He signed on with the Metropolitan Opera in 1945 and debuted there that year as the elder Germont in “La Traviata.”

“Mr. Merrill displayed a rich, vigorous baritone, ample in volume, effortlessly and surely produced,” critic Robert A. Hague wrote at the time.

Merrill was born June 4, 1919, the son of shoe salesman Abraham Merrill and Lillian Balaban. His mother had an operatic and concert career in Poland before her marriage and guided her son through his early musical training.

Growing up in Brooklyn, Merrill was first inspired by music as a teenager when he saw a Metropolitan Opera performance of “Il Trovatore.” The young baritone paid for singing lessons with extra money he earned as a semipro baseball pitcher.

Merrill is survived by his wife, a son, a daughter and his grandchildren, Mr. Tucker said.