THOUGH HARDLY ranked with Wotan, Rigoletto or the Count di Luna, Professor Harold Hill should be a role to please music fan Tony Randall.

The actor, who has been making a second career on the air as the land's most passionate opera buff, might have gloried more with Wagner or Verdi for his Wolf Trap week starting Tuesday, but Meredith Willson's "The Music Man" fits Randall's double image neatly.

There's irony here. Randall's only Broadway musical, "Oh, Captain," has sunk without a trace of revival. "It was a nice little show," he says now, "but we had the impossible barrier of opening on the heels of two super musicals, 'West Side Story' and 'The Music Man.'"

"Oh, Captain!" was adapted, 21 years ago, from a vastly popular Alec Guinness film, "The Captain's Paradise." Even for its period, 192 performances could not be called a hit. Listening to the original cast recording the other day, I remarked that the Jay Livingston-Ray Evans score sounded more than adequate.

"It holds up nicely, but what that record lacks," replied Randall, "is the 12-minute ballet I did with Alexandra Danilova. The music was improvised during rehearsals and here was this great ballerina leading me around, giving me some marvelously clever tricks. We had a ball doing it."

Because of Randall's phenomenal success as Felix, the fussy one, in TV's long-running "The Odd Couple" and his Doris Day-Rock Hudson comedies, one thinks of Randall as a farceur, one of the sharpest of the light comedy breed.

Such categorizing is unfair because Randall is, as he proudly calls himself, "an actor."

Lingering not long enough to graduate from either Northwestern or Columbia universities, Anthony Randall, so programmed, was 21 when he made his off-Broadway bow in a Chinese fantasy in the spring of 1941.

He vows that his "real education" began at New York's Neighborhood Playhouse under Sanford Meisner and MArtha Graham, a school of which he now is vice president. That led him to play Marchbanks to Jane Cowl's Candida and in Ethel Barrymore's "The Corn Is Green."

The day after he began rehearsals with Tallulah Bankhead in "The Skin of Our Teeth," Randall was drafted for a four-year run with Uncle Sam as a Signal Corps officer.

"The first job after that," Randall happily looks back, "was with Katharine Cornell, first as the blubbery brother in 'The Barretts of Wimpole Street' and then as Scarus in her production of 'Antony and Cleopatra.'

"What a cast she picked for that! Also in bit roles like mine were Charlton Heston, Eli Wallach and Maureen Stapleton.There were Alan Shayne, who's become a major casting director, Godfrey Tearle as Antony, David Stewart, Robert Duke, Joseph Wiseman, douglass Watson, Kent Smith and Charles Nolte, who scored as Billy Budd and then turned to playwriting and teaching. There was Lenore Ulric, once a major Broadway star, none bigger, in a very small role, Charmian, the keeper of the asp. Miss Cornell always saw to it that Miss Ulric had a stage-level dressing room, a star's prerogative, even if it meant she herself dressed upstairs. For all of us, wholly unknown then, it was exciting.

"That also was the beginning of TV. We all became TV babies with Fred Coe and his Studio One, the Daddy of Live TV.

"I made my first hit on 'Mr. Peepers' and people still seem to remember me from that."

A forgotten slice of Randall's carrer, though not forgotten by him, is the summer of 1946, when he directed at Washington's Olney Summer Theater.

"The play I most fondly remember directing there was Behrman's 'Biography,' with Mimi Norton and Jack Salemanca, whom she later married, long before he made his name as a novelist. Now they have a son who wants to go into the theater? What could be more natural?

"The longest run I had on Broadway was in 'Inherit the Wind.' I played the H.L. Mencken-like character in Paul Muni's company. What training that gave me!

"The film version of 'Oh, Men, Oh, Women' took me to Hollywood, not for my stage part but another. That started me in movies, some 25 I think, and, come to think again, when Jack Klugman and I were cast together for what became 114 episodes and five tours of 'The Odd Couple,' we were just picking up where we'd begun together in the early days of live TV."

Through all those West Coast years, Oklahoma-born Randall and his school-mate-wife Florence have kept their apartment on Central Park West, once a half-hour hike to the Metropolitan Opera House. With the Met's move up to Lincoln Center, the Randalls are only minutes away.

Another haunt of the Randalls is placid, family-oriented and wholly unflashy Fair Harbor on Fire Island, where there were such neighbors as Charles Collingwood, his wife, actress Louise Allbritton, Thelma Ritter, Peggy Tait Snow and Enid Markey.

"Because I've been doing the summer stage circuit for the past six years," sighs Randall, "I've not been there in too long and we miss it.

"As for what happens to me after this week at Wolf Trap and our final three at Baltimore's Morris Mechanic, I may enter a rest home.

"But I also have one rule: I never say what's going to be next until the contract has been signed. I hardly think I'll be drafted the way I was after a day with Tallulah. I just think it's bad luck.

"Doing 'The Music Man' this summer was almost a challenge. I guess I wanted to see if I could still leap around, and I do like the sound of the orchestra tuning up for the overture. It's not opera but it does give me a tingle and I know I can sing those songs.

"We began this 14-week tour at the St. Louis Muny Opera and have an exceptionally classy cast for summer touring, Benny Baker, Jack Washburn and Barney Martin, who acted Terwilliger, the court stenographer, with me and made such a hit in 'Chicago.' There's Linda Michele and Nancy Cushman, a fine actress people are surprised to find singing as Eulalie Shinn, the mayor's wife.

"But that's it, isn't it? We're not personalities. We're actors playing other people, sometimes with music, sometimes without. First of all we're actors."