Using coffee and milk, he creates faces, animals and logos that have gone viral on social media, landed him job offers in New York and Australia, and earned him the title Barista Brian.
He says he never imagined foam designs, done in under two minutes, would be his artistic medium.
"It's such a funny thing that's happened to me, and how it's escalated to the level I'm doing it at now is just incredible because it's so far fetched and seems a little bit ridiculous at times," he said.
Leonard says he's always been creative. He remembers drawing unicorns all over his childhood home, using the walls behind TVs and doors as his canvases
"My poor parents just put up with it," he said. "It was sort of like I was doing graffiti and it was my tag and I'd feel sneaky."
He took art classes at the Beaverbrook Art Gallery and did musical theatre growing up, but only discovered his coffee calling about two years ago while working as a bartender with an expresso machine.
When he realized he could make designs in the coffees just by pouring the milk, he started drawing co-workers' faces.
"The reaction I got from them was so outstanding that I started doing it for … anyone who came in and it was just a hit … and it just kind of went from there."
Leonard went on to become a barista at The Coffee Bar, where he continues to hone his time-sensitive technique.
"It's always like my heart will be pounding and it's a creative surge of energy because I know that I have to be quick," so the coffee doesn't get cold, "but I also have to do my best."
He says elephants have become a bit of a trademark for him because they're relatively easy to do, yet impressive. But he always takes requests.
"I like to ask people if there's anything I can make for them. A lot of the time people don't understand what I mean when I say, 'Is there any design I can put in your coffee?'" because latte art is still a relatively new trend.
Last month, a woman asked him to make a Blue Jays logo in her husband's coffee and it turned out the man does marketing for the team. He posted a photo of Leonard's design on Instagram and it became the team's most-liked post ever within 12 hours.
It also received 14,000 likes on Facebook within a day and ended up getting picked up by mlb.com as its photo of the day.
"It's just been so wonderful," said Leonard. "I'm so happy to share my artwork."
And while it can sometimes be upsetting that his art doesn't last, he says "that's almost part of the art of it.
"It's not meant to last. It's just there to make an impression and then it's to be enjoyed. It's drinkable art."