No artist did more to legitimize rock music as a serious art form than the Beatles — and perhaps no accolade symbolized that shift more than the band's magnum opus, Sgt. Pepper's Lonely Hearts Club Band, the first rock LP to win Album of the Year at the 10th Annual Grammy Awards on Feb. 29, 1968.

The Fab Four had shown a staggering amount of growth since winning their first two Grammys — Best New Artist and Best Performance by a Vocal Group for "A Hard Day's Night" — in 1965. The Rubber Soul track "Michelle" earned them another trophy for Song of the Year in 1967. Still, the most coveted prize of the ceremony had eluded them so far, with Help! and Revolver losing back-to-back years to Frank Sinatra's September of My Years and A Man and His Music, respectively.

The Chairman of the Board had won Album of the Year three times in the Grammys' first nine years, leading a pack of recipients that also included Henry Mancini, Judy Garland, Stan Getz, Joao Gilberto and even comedians Bob Newhart and Vaughn Meader. Many establishment types still viewed rock 'n' roll as a childish novelty, hardly deserving of the music industry's top honor.

But even rock's staunchest opponents were no match for the paradigm-shifting Sgt. Pepper. The album captured the zeitgeist of the late-'60s counterculture and almost singlehandedly ushered in the Summer of Love upon its release in late May 1967.

It topped the charts on both sides of the pond and sold more than 30 million copies worldwide. It further cemented the LP as the predominant medium of music release and consumption.

Watch the Beatles' 'A Day in the Life' Video

It was fitting, then, that the Beatles finally defeated Sinatra in their third consecutive clash for Album of the Year, with Sgt. Pepper triumphing over Francis Albert Sinatra & Antonio Carlos Jobim. The psychedelic opus also beat Vikki Carr's It Must Be Him, Ed Ames' My Cup Runneth Over and Bobbie Gentry's Ode to Billie Joe.

Sgt. Pepper also won Best Contemporary Album, while engineer Geoff Emerick was honored with Best Engineered Recording, Non-Classical, and art directors Peter Blake and Jann Haworth collected the golden gramophone for Best Album Cover, Graphic Arts. Notably, none of the Fab Four attended the Grammys for their big win, as they had recently flown to Rishikesh, India, with their significant others to study Transcendental Meditation at the ashram of the Maharishi Mahesh Yogi.

Paul McCartney would become the first Beatle to grace the Grammys stage in 1971 when he accepted the award for Best Original Score Written for a Motion Picture for Let It BeRingo Starr appeared in 1973 to co-present Best Male R&B Vocal Performance to Billy Paul's "Me and Mrs. Jones" with Harry Nilsson and to accept Album of the Year for George Harrison & Friends' Concert for BangladeshJohn Lennon made his Grammys debut in 1975 when he and Paul Simon co-presented Record of the Year to Olivia Newton-John for "I Honestly Love You." Harrison, who died in 2001, never set foot on the Grammys stage.

Sgt. Pepper marked the first of four Grammy wins for Emerick, who was just 22 years old at the time. Half a century later, the engineer still considered the LP's final track the high point of his work with the Beatles.

"Perhaps the greatest peak of all was the production of 'A Day in the Life' on Sgt. Pepper," Emerick told Variety in 2017. "John first played an acoustic version of the song for George Martin, and I heard it and told a colleague, 'Wait until you hear this.' I still had the shivers. And the night we put the orchestra on it, the whole world went from black and white to color."

Beatles Albums Ranked

From the cheery 'Please Please Me' to the kinda dreary 'Let It Be,' we rank all of the group's studio LPs.

More From WBSM-AM/AM 1420