One of the first times Otis Williams, the founder and last surviving original member of the Temptations, realized his music made an indelible impact on their fans occurred after he received a letter in the mail. “I’m reading it and it said to give them a call the first chance I had,” Williams remembers. “She gets on the phone and told me she was ill and asked: ‘God, don’t take me until I speak to Otis Williams.’ She said she wanted to tell me how much the music meant to her before she died. I didn’t have any idea when we started making this music to just have fun and make money that it’d be so emotional for people.”

It’s a sentiment that has lasted through the Temptations’ success, as they have held onto the distinction of being one of the most commercially dominant vocal groups in music history. With 14 R&B No 1 singles under their belts (among them: My Girl, The Way You Do the Things You Do, Cloud Nine, Papa Was a Rolling Stone and Get Ready), their music provided a soundtrack to the 60s and early 70s, helping lift up Motown Records in the process.

Despite launching over a half-century ago, the Temptations and their legend has lately been enjoying fresh relevance. A jukebox musical, based on their rise and told from the perspective of Williams dubbed Ain’t Too Proud (named after their 1966 signature Ain’t Too Proud to Beg) debuted on Broadway in March and later garnered 11 Tony nominations, winning for best choreography. In addition, Williams was recently honored at the Apollo Theater’s recent Spring Gala where he was bestowed a spot on the historic Harlem theater’s Walk of Fame. “Here I am, 77 years old and I’m enjoying my life as if I’m 27,” Williams says to the Guardian. “I am profoundly blessed to be doing what I’m doing 59 years later.”

Williams, who grew up in Texas, packed up and moved to Michigan with his mother when he was 10 (his parents separated shortly after Williams was born). As fate would have it, he wound up in Detroit just as the city’s homegrown Motown Records (founded by Berry Gordy and named, of course, after the city’s then claim to fame as the automobile capital of the world) was in its infancy. “It was happenstance,” Williams says now, who initially found trouble in the city but later found solace in music, later founding the Temptations with its original lineup of Al Bryant, Eddie Kendricks, Melvin Franklin and Paul Williams. “It was necessary timing and it was meant to be that God in his infinite wisdom put all of these producers, writers and artists together at that time and made such profound music.”

David Ruffin, Melvin Franklin, Paul Williams, Otis Williams and Eddie Kendricks of the Temptations pose for a portrait in 1965. Photograph: Michael Ochs Archives/Getty Images

Among that crew was Smokey Robinson, the young singer-songwriter who penned a track that would help rocket the group to superstardom. “I remember we were performing at the (long defunct Detroit nightclub) The 20 Grand and Smokey said: ‘I have a song for you guys,’” recalls Williams of the birth of their signature My Girl. “When [arranger] Paul Riser added the strings and horns, I came into the studio and Smokey was sitting at the console. I said: ‘I think we have something.’” After its release in December 1964, the song became the act’s first No 1 hit that March. “I remember Berry Gordy, the Beatles and the Supremes all sent telegrams congratulating us. But then everywhere we went, we heard My Girl. It happened so much it was like, ‘Jesus Christ, we have other songs: play something else!’”

Despite their immense success and stature as R&B’s premier act, Williams is quick to note it wasn’t always easy. “We were sky high and we were enjoying what we were doing, but we started fragmenting,” he says. As the musical jokes, their nickname the Temps eventually obtained a new meaning with a range of members cycling in and out of the band over the years. Longtime lead vocalist David Ruffin (younger brother of Motown solo act Jimmy Ruffin) took over for Bryant three years after their founding, while Ruffin himself was unceremoniously kicked out the group in 1968. “We started letting matter what shouldn’t matter. Egos and drugs got in the way.” Since their founding, 26 members have been part of the group, which still tour today. “In my home, there’s a big painting of a friend of mine made of all of the Temptations. I stand there and look at that painting and think how I had to deal with 24 strong personalities, and here I stand today.”

Ephraim Sykes, Jawan M Jackson, Jeremy Pope, Derrick Baskin and James Harkness in Ain’t Too Proud. Photograph: Matthew Murphy

The Ain’t Too Proud musical depicts a warts-and-all look at the group, which not only doesn’t sugarcoat their story but acknowledges their trials and tribulations head-on. Among them: the aforementioned lure of drugs and alcohol, Ruffin’s abusive attitude towards women (his character is even depicted striking girlfriend, fellow Motown singer Tammi Terrell, during a picnic) and Williams’ own relationship with his son, Lamont. Due to his hectic touring schedule, Williams’ character bemoans missing out on Lamont’s youth and the story reaches an emotional apex when it’s revealed he tragically died in a construction accident at 24 years old. “It’s a mixture of both pain and therapy,” says Williams of seeing his life dramatized for the stage, played by the actor Derrick Baskin, who earned a Tony nod for his portrayal as the singer who tried to cope with fame and wrangle his fellow members. “I always tell people, the world loved the Temptations but the Temptations didn’t love themselves. Drugs came into play and once that happened, dreams and aspirations became fragmented. I am thankful to God for being able to withstand it all.”

Williams stands as the last surviving member of the group’s core members, with Paul Williams dying by suicide in 1973, Bryant succumbing to alcoholism in 1975 and Franklin and Kendricks passing away from various health ailments during the 90s. Ruffin, meanwhile, died of a cocaine overdose in 1991. Much like the success of the group themselves, Williams’ later years are bittersweet: he’s left without his bandmates, but is enjoying a newfound relevance with a feature film in the works and Ain’t Too Proud gearing up for a global tour next year. He also takes solace in knowing the indelible impact of his hits. “This music is so lasting that even when we are no longer here, it’ll still be loved,” he says. “It’s undeniable and also something I would have never imagined.”