Music-biz veterans watching the concluding episode of HBO’s terrific two-part Sinatra documentary last week were surprised and delighted to hear the voice of Mo Ostin as he recounted his role in the launch and running of Frank’s label Reprise in 1960. The legendary music man, who went on to become the Chairman of Warner/Reprise during its glory years, never grants interviews. Here’s more detail on what would retrospectively be seen as the genesis of one of the greatest, most artist-friendly record company of rock’s golden era.

Ostin was introduced to Sinatra in 1960 by Frank’s longtime attorney, investment partner, consiglieri and close friend Milton “Mickey” Rudin (pictured at right), a colorful character with a Harvard Law degree who repped a constellation of luminaries including Marilyn Monroe, Elizabeth Taylor, Lucille Ball, Cher, Marvin Davis, Steve Wynn, Norman Lear, Steely Dan, the Jackson Five and the Aga Khan. From 1949 to 1966, Rudin was a partner in the prestigious L.A. firm Gang Tyre Ramer & Brown.

“You have to understand the scope of his relationship with people,” said Rudin’s longtime friend publicist Lee Solters. “He knew them all, not just on the American soil, but all over. And he was feared. When people said, ‘You'll have to deal with Mickey Rudin,’ they thought, ‘Oh, God.’”

At the time, Mo was serving as Administrative Executive and Controller (i.e., chief accountant) of renowned label Verve Records for jazz impresario Norman Granz, whose credits include producing the Ella Fitzgerald Songbook series for and creating the historic Jazz at the Philharmonic series; Granz had founded Verve in 1956. Interestingly, before starting Reprise, Sinatra tried to buy Verve from Granz, who sold it to MGM later in 1960.

Initially, Sinatra signed his Rat Pack pals including Dean Martin and Sammy Davis Jr., as well as contemporaries like Bing Crosby, Jo Stafford, Rosemary Clooney and Redd Foxx, putting Reprise and its President at a disadvantage in competing with labels that were loading up their rosters with younger rock and R&B acts. Frank—whose nickname “Chairman of the Board” derived from his active role at the label—famously despised rock & roll and continually denied Mo’s entreaties to back off from his edict.

That changed in 1963, when Sinatra, fed up with Reprise’s anemic sales, sold the label to Jack Warner’s Warner Bros. Pictures, which had established its own label in 1958. Initially, Warner Bros. Records had been as out of touch with the times as Reprise, putting out records by contract players like Tab Hunter, Edd “Kookie” Byrnes, Connie Stevens and Jack Webb. It wasn’t till 1961 that the label’s fortunes turned around with the signings of Trini Lopez, comic Allan Sherman and Peter, Paul & Mary, soon after the arrivals of new ranking exec Mike Maitland and promotion head Joe Smith. All scored massive hits.

With the sale, Warner Bros. and Reprise were merged under Maitland, with Ostin second in command, while the personable Smith became the face of the labels. While the old-school Maitland served as a figurehead, Ostin—described by author/archivist Barney Hoskyns in his book Hotel California as “a bean-counter with soul”—began making the creative decisions in tandem with young A&R exec and staff producer Lenny Waronker, the son of Liberty Records founder Sy Waronker. Together, Mo, Joe and Lenny transformed Warner/Reprise, signing and having success with such acts as The Beau Brummels, The Kinks, Petula Clark and Harper’s Bizarre, followed by The Grateful Dead, Jimi Hendrix and Van Morrison.

The Warner/Reprise story became even more magical in 1969, with the acquisition of Warner-Seven Arts—of which Atlantic Records was now a part—by Kinney Corp., whose CEO, Steve Ross, turned out to be one of the most enlightened entertainment moguls in history, initiating three decades of prosperity, creative risk-taking and acclaim throughout the music and movie businesses.

“We got the break of our lives,” Joe Smith told Hoskyns. “Steve Ross believed that the management of creative companies was the key. The artists will come and the artists will go, but Mo and Joe and Ahmet and Jerry will be there. He just let us do it.”

Ross happened to be another client of Mickey Rudin.