Phil Donahue, whose pioneering daytime talk show launched an indelible television genre, has died.

Phil Donahue, whose groundbreaking daytime talk show launched an indelible television genre that produced household names like Oprah Winfrey, Montel Williams, Ellen DeGeneres and many more, has died. He was 88.

According to NBC’s “Today” program, citing family members, Donahue died Sunday after a long illness.

Donahue, who was nicknamed the “king of the daytime talk shows,” was the first to add audience participation to a talk show, usually for a full hour with one guest.

“Only one guest per show? No band?” he recalled being asked frequently in his 1979 memoir, “Donahue, My Own Story.”

The format distinguished “The Phil Donahue Show” from other interview programs of the 1960s and made it a trendsetter on daytime television, where it was particularly popular with female audiences.

Later renamed “Donahue,” the program launched in 1967 in Dayton, Ohio. Donahue’s willingness to explore the hot social issues of the day was immediately apparent when he had atheist Madalyn Murray O’Hair as his first guest. He would later broadcast shows on feminism, homosexuality, consumer protection and civil rights, among hundreds of other topics.

The show was syndicated in 1970 and aired nationally for the next 26 years. The show won 20 Emmy Awards for the show and for Donahue as host, and a Peabody Award for Donahue in 1980. It also featured radio-style call-ins, which Donahue greeted with his signature, “Is the caller there?”

The show’s final episode aired in 1996 in New York, where Donahue was living with his wife, actress Marlo Thomas, at the time of his death. The two had been married since 1980. Donahue had five children, four sons and a daughter, from a previous marriage.

Donahue returned to television briefly in 2002, with another “Donahue” show on MSNBC. The network canceled the show after six months, citing low ratings.

He was born Phillip John Donahue on December 21, 1935, to a middle-class Irish-Catholic family in Cleveland. They moved to Centerville, Ohio, when Donahue was still a child, where he lived across the street from Erma Bombeck, the future humorist and columnist.

Donahue was a member of the first graduating class of 1953 at St. Edward High School, a Catholic boys’ school in Lakewood, and graduated from the University of Notre Dame in 1957 with a degree in business administration. He later rebelled against the church and left it, though he poignantly noted in his book that “a little piece” of his faith would always remain with him.

After several previous stints in radio and television, Donahue was invited in 1967 to move a former radio talk show to Dayton’s WLWD television station. In 1974, the program moved to Chicago, where it remained for many years until it ended its run in New York.

The show featured discussions with spiritual leaders, doctors, housewives, activists and entertainers or politicians who might be passing through town. He said finding the show’s winning formula was a happy accident.

“It may have been three years before any of us began to understand that our program was something special,” Donahue wrote. “The style of the show was not developed by genius but by necessity. The usual talk show hosts were not available to us in Dayton, Ohio. …The result was improvisation.”

That gave the show a freedom that endured as it grew to become #1 in its class.

With a suave style and a head of salt-and-pepper hair, Donahue boxed with Muhammad Ali. He played soccer with Alice Cooper. His guests gave cooking lessons, taught breakdancing and, more controversially, described mansharing, being a mistress, lesbian motherhood or — with the help of collected videos that got the shows banned in certain cities — how natural childbirth, abortions or reverse vasectomies worked.

A stop at “Donahue” became a must for leading politicians, activists, athletes, business leaders and entertainers, from Hubert Humphrey to Ronald Reagan, Gloria Steinem to Anita Bryant, Lee Iacocca to Ray Kroc, John Wayne to Farrah Fawcett.

In addition to his famous talk show, Donahue was involved in several other projects.

He teamed with Soviet journalist Vladimir Posner for a groundbreaking Cold War television discussion series in the 1980s. The US-Soviet Bridge featured simultaneous broadcasts from the United States and the Soviet Union, with studio audiences able to ask each other questions. Donahue and Posner also co-hosted a weekly roundtable discussion, Posner/Donahue, on CNBC in the 1990s.

Donahue also co-directed the 2006 Oscar-nominated documentary “Body of War.”