Justin Guarini Is Glad He Didn't Win 'American Idol' : 'I Was Not Ready'

Justin Guarini talks with PEOPLE about his family, his new role in Broadway's In Transit, and why not winning American Idol was actually for the best

He came in second place on the inaugural season of Fox's megahit American Idol. But looking back on it, Justin Guarini sure is glad he didn't win.

The 38-year-old singer and actor — currently earning rave reviews for his turn in Broadway's new musical In Transit — told PEOPLE that while there are things he would have changed about his time on the show, beating out Kelly Clarkson for the top prize isn't one of them.

"I think my life would have gone differently had I won," Guarini said. "I was not ready, and I was just naïve. I believed I was going to work hard and people would take care of me — and that's not how the business works. You have to create your own brand and be the loudest trumpet for yourself. There's a way you can do it with grace and class, but I don't know if I would have learned those things had Idol gone differently."

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"It was a really great lesson I learned on Idol," he added. "Once the lights went down on that show, you realize you're kind of on your own. Even the success that Kelly had, she really had to work hard for that — that wasn't handed to her. She has come out of that with flying colors and only a few of the winners really truly have. That is due in large part to the work they put in."

Guarini has put plenty of work into his own career. The son of a CNN anchorwoman and a police chief, he grew up singing — starting when he was just 4 years old in the Atlanta boys choir. That continued throughout junior and high school, as he made his way through the Philadelphia archdiocese choir before studying musical theater and vocal performance in college.

Back then, it was Guarini's dream to be on Broadway — specifically in Disney's Tony-winning blockbuster, The Lion King. After years of auditioning for the show, he finally got a call from casting agents offering him an ensemble role in the production.

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It was a thrilling moment, but Guarini couldn't accept the role. It was 2002, and he was on his way to Los Angeles to compete on Idol. "That was my fork in the road," Guarini reflected. "I chose Idol and it ended up being this amazing 10-year career of not only recording and touring but also hosting live red carpets and doing in-studio shows."

He'd eventually make his Broadway debut — in 2010's Women on the Verge of a Nervous Breakdown. It was a shot that brought Guarini back where he started… literally. "Our opening night party was at the Millennium hotel, in one of the conference rooms where I auditioned for Idol," Guarini said, laughing. "It was a full-circle moment."

After starring in six Broadway and Off Broadway shows in six years (including Wicked, American Idiot, and Romeo and Juliet opposite Orlando Bloom), Guarini would have another full-circle moment with In Transit.

The a capella musical — Broadway's first-ever — is a continuation of the work Guarini first started over 20 years ago, when he co-founded a high school a cappella group. (They called themselves Midnight Soirées, and their album can be found on the interwebs for those who have the patience to search).

In Transit is the most challenging project Guarini said he's ever tackled. He and the show's cast of 11 sing every note in the hour and 40-minute musical, which features vocal arrangements from Pitch Perfect's Deke Sharon and a book, music, and lyrics by Oscar winner Kristen Anderson-Lopez (Frozen) alongside James-Allen Ford, Russ Kaplan, and Sara Wordsworth.

"There's no mold… we're making it," Guarini said. "The show has all the elements you would see in any other Broadway show — the choreography, moving set pieces, etc. However, we are the orchestra. Every single sound you hear, whether it's a sound effect or a drum or it's a number, comes from the human mouth. We are all that there is."

RELATED VIDEO: Justin Guarini On Starring in Broadway's First A Cappella Musical, In Transit

Among the roles Guarini plays in the show is Trent — a gay, successful, talent agent living in New York and struggling to come out to his ultra-conservative Texas family despite his engagement to boyfriend Steven (Telly Leung, of Glee).

"I've had people come up to me and tell me, 'This is my story — I've lived this.' To be able to help someone break through some of those barriers is probably the biggest honor for me every night," he explains.

Off stage, Guarini's relationship is far less complicated. He married Reina Capodici — whom he first met in junior high school where Capodici's mother was his English teacher — in September 2009. The couple live in Doylestown, Pennsylvania with their three kids: 11-year-old daughter Lola and sons Asher, 3, and William, 5.

They're a musical family, and often show off on Instagram by singing and dancing. Though they've seen more of Guarini's "Lil' Sweet" character from his recent Dr. Pepper commercials than they have his Broadway roles, Idol performances or From Justin to Kelly, Guarini wouldn't stop them from pursuing a career in the business… just as long as they stay grounded.

"It's so easy to get lost in the smoke and mirrors of the entertainment business — to believe your own hype," Guarini admits. My family keeps me grounded. And why I do what I do — why I commute five hours a day and work harder now over these years than I will ever in my life, is because of my family."

As for Idol, 15 years later, Guarini still finds himself very grateful for the platform — and doesn't think the show's cancellation last season will be its final chapter. "It was an awesome experience," he said. "It launched a thousand ships — introduced us to wonderful people whose careers go beyond just recording. I believe it will be back."

In Transit is now open at Broadway's Circle in the Square Theatre.