"We grew up in the Baptist church, but I don't have memories of singing gospel music," he reflects. "People often ask me if I grew up singing gospel and I say 'no,' but I didn't grow up singing classical music either."

In fact he even studied science in junior high school rather than the arts, but he began singing in the school choir as an extra activity. "I progressed in singing year by year, and I won my first competition in my last year of junior high," he remembers. "That was my first lightbulb moment, that maybe I could pursue a musical career one day."

It was when he attended Manhattan's La Guardia high school that his musical and creative abilities really began to flourish. "La Guardia was probably the first performing arts high school in the country, it was a bit like [TV show] Glee," he says.

"It was great,  I learned so much there. It was really eye-opening in terms of repertory and options and languages. I performed in my first opera in my sophomore year, I think I was 15."

That opera was La Costanza in Amor Vince l'Inganna by the baroque composer Antonio Caldara, though it wasn't the baroque era that would particularly catch Noah's attention. What especially fascinated him was the collection of CDs and laserdiscs held by the principal of La Guardia's vocal arts programme, which featured classic performances by artists such as Herbert von Karajan, Pavarotti, and soprano Leontyne Price.

"I'd get to school early so I could watch a new scene before class began. I just became transfixed with opera, and because learning a language was part of the course I took Italian. I figured I like opera, so I should learn Italian so I can understand what they're singing."

In one of those serendipitous moments that life sometimes serves up, Leontyne Price came to New York's Tower Records (which was across the street to Juilliard) on a promotional visit to launch her enormous "Essential" CD collection. The star-struck Noah queued to meet her.

"I said to her 'Miss Price, you are such an inspiration, you've really drawn me to opera', and she said 'what's the next step for you?' I said Juilliard, and she said 'that's the best place for you'. She gave me a few hints about my repertoire, and the last thing she said was 'give 'em hell!'"

Inspired by this brush with musical greatness, Noah won a scholarship to the esteemed Juilliard School (though, he adds, "I applied to about seven music schools and I got accepted by all of them"). Juilliard has a reputation for being demanding and intensely competitive, and Noah found that it was well deserved.

"I was 17 when I went there, and I was still learning how my voice works. You have to build it slowly and everything wasn't all working yet.

"But the amount of knowledge I gathered there was amazing, and graduating from Juilliard was an artistic feat but it was also a spiritual journey. I was so much stronger when I left because I'd been through it."

By the end of his senior year at Juilliard, Noah's abilities were already beginning to create ripples in the classical music world, and his achievements earned him  inclusion in the book Spirit of Harlem by Craig Marberry and Michael Cunningham.

However, perhaps prematurely, he decided that he was going to take a shot at launching himself on a professional career, and with that in mind he turned down a scholarship at the Manhattan School of Music. But like many a musician before him, he found that making a living from music is hard.

"I wanted to be like Pavarotti at 20 years old, but it didn't happen," he admits.  "I had to take a year off, which became three years. I did auditions and entered competitions, and I was successful in the beginning and then I hit a wall, where everyone said 'no no, you're not ready yet'. "

You might say this period of his life was character-building, as he took a series of jobs to help him survive while he continued to perfect his singing. He worked as a carpenter's assistant at Juilliard, and did a stint as a cater-waiter, serving food at catered functions. And as we have seen, he made it to Carnegie Hall, but not in the way he'd dreamed of.

Luckily he was saved in the nick of time by San Francisco Opera, who accepted him into its Merola summer program after he'd auditioned for it in New York. "I think that was the breaking point - if they hadn't said yes I would have quit singing. That was my last audition."

Instead, Noah enjoyed a superb summer in the City by the Bay, appearing in his first modern opera when he sang the role of the Wizard in Conra Susa's Transformations (a role he later repeated at Wexford in Ireland).

Then he was invited to join the San Francisco company's fellowship program for young artists. During a three-year stint in California, he made his professional debut in the world premiere of Philip Glass's opera Appomattox, and he vividly remembers the night he went onstage as Macduff in Verdi's Macbeth after the incumbent tenor fell ill.

"I was singing Malcolm and understudying Macduff," he recounts.  "The tenor was having a little bit of difficulty in the first act, and when the curtain came down the director asked me if I was prepared to sing the role.

"I said yes, and before I went onstage I visualised the role the way a pro athlete would before a race. I went on, and it was a huge success. After that I moved back to New York and got an agent. I used that moment to start my career."

Subsequently, Noah has been steadily climbing the operatic ladder, mastering roles in both mainstream and brand new repertoire. He sang The Prince in the first fully staged production of John Adams's A Flowering Tree with Chicago Opera Theatre - "John Adams is an awesome guy and so down to earth," says Noah, "and he was very happy to make adjustments to help me feel more comfortable" - and his numerous other engagements have included singing Cavaradossi and Rodolfo for Michigan Opera Theater,  Narraboth from Strauss's Salome for Arizona Opera, Aeneas from Dido and Aeneas with the Yards Arts Festival, and Don Jose in La Tragédie de Carmen with Chicago Opera Theatre.

At the Castleton Music Festival, he sang Luigi in Puccini's Il Tabarro under the baton of the eminent Lorin Maazel.

"Singing in front of maestro Maazel, I was a bit nervous," Noah confesses. "But he's very laid-back and he liked my singing. We were really in sync during the performances."

Other memorable experiences recently have included touring Carmen in South Africa with Opera Africa, and La Boheme in Opera Carolina. "I love Boheme because the characters are just young guys, it's like [TV show] Entourage, like singing Entourage in Italian in Paris!" Noah enthuses. "Though they have less money of course, and no iPhones or anything. Every day is a struggle for them to eat and to live, but they make the best of it."

In 2012 Noah will make his Covent Garden debut as Hassan in Judith Weir's Achterbahn (Miss Fortune), having premiered the role in Bregenz in Austria in 2011, and British audiences can also look forward to seeing him in Opera North's Madame Butterfly.

It feels like several lifetimes have passed since the young Noah first told his mother, Patricia, that he wanted to become an opera singer.

"My mother's fantastic! a real inspiration" he declares. "She's been working as a cashier at Food Emporium in Harlem for 42 years - can you believe that?

"When I said I wanted to sing opera she always supported me, and when I got to Juilliard she could see that I really had what it takes. I always think of her as almost like my agent or one of my managers in New York."

His music is making him a global citizen, but Noah Stewart has no plans to forget his roots.

Adam Sweeting