The 23-year-old has a sound that's both timeless and fresh, blending old-school jazz crooning with the R&B vocalists she grew up on.
She's not a household name yet, but those who know, know.
And last month, the Grammys gave her the ultimate seal of approval - awarding her best jazz vocal album and, more significantly, best new artist.
Recent winners of the latter prize include household names like Billie Eilish and Olivia Rodrigo. To win, Joy had to beat chart regulars like Latto, Måneskin and Wet Leg.
Speaking in London a month after the ceremony, she recalls the moment Rodrigo opened the envelope and read her name.
"My eyes were closed and I was holding my little brother's hand; and when she said my name it was like, 'Oh shoot, oh shoot, oh shoot!'
"All these people stood up for me, Adele, Lizzo, Taylor Swift... so I was completely flushed, completely humbled."
But when she got to the stage, a chilling realisation set in.
"I'd left my phone behind," she laughs, "so my whole speech was just sitting at the table!"
After bashfully improvising her thank-yous, the night improved immeasurably.
"Beyoncé told me congratulations after the show, which was ridiculous. Me in the same room as Beyonce? And her knowing of my existence? It's just crazy."
By this stage, however, Joy should be accustomed to receiving honours.
Although she only took up jazz five years ago, she's already won the Sarah Vaughan International Jazz Vocal Competition, and been awarded the Ella Fitzgerald Memorial Scholarship.
Her voice is warm and mellifluous, lingering over notes like she's savouring wine, and simmering with emotional intensity.
She credits some of that to her producer/manager, Matt Pierson, who told her to "pretend as though a microphone is the person's ear that's listening to you".
But she also possesses an innate ability to take an old standard and make it seem like the lyrics were torn from her diary.
It's an approach that causes confusion for fans who aren't well versed in the jazz repertoire.
"People are like, 'I love your song, Guess Who I Saw Today?' And I'm like, 'I wish it was mine!" she says of her most recent single, originally made famous by Nancy Wilson.
"Others are like, 'Wow, I didn't know about that song before and it's a really great story'. I find it amazing that people connect with it."