Early on in high school, when “Dancing with the Stars” was sweeping television, Samantha Gillis and some friends were inspired to take up a new hobby.

Ballroom dancing didn’t stick for the others, but Gillis knew then that she had stumbled on something life-changing.

“It was how I found myself,” the 21-year-old Trumbull native said.

In 2015, Gillis earned first place in her division at the United States Dancesport Championship, one of the nation’s largest ballroom dancing competitions, beating seasoned dancers in her 20-to-35 age group.

“It’s a big boost of confidence to be able to do that,” Gillis said. “The girl who came in second place was married and there with her husband — I was there with my dad and dancing partner.”

Gillis alternates between two dancing partners, Marko Urosevic and Marko Paunovic, who are also her instructors at Fred Astaire Dance Studios in Trumbull.

Gillis will perform with them this Saturday, Feb. 27, at Holy Trinity Greek Church in Bridgeport, where all dancers, novice to pro, are welcome to join.

Because they’re teachers, Urosevic and Paunovic are considered professional ballroom dancers, while Gillis, who doesn’t teach, is an amateur. Next in her career, which Gillis plans to pursue professionally, is finding an amateur partner with whom she can practice and compete more frequently.

Gillis has no doubts about pursuing ballroom dancing, which nowadays, unlike other types of dance, is treated primarily as a sport. At competitions, dancers are scored on their technical execution and can advance in the ranks.

American ballroom dancing competitions have two categories. “Smooth” encompasses waltz, tango, foxtrot, and Viennese waltz. “Rhythm” includes cha cha, rumba, East Coast swing, and bolero.

“There are a lot of different characters you’re playing,” Gillis said. “A waltz is very romantic. A foxtrot is very playful and jazzy. And samba has this beat and this pulse.”

For Gillis, a self-described perfectionist, the structure and routine of dance was an instant draw. “There’s always something else you can can work on, which is so satisfying,” she said. “You’re never complete.”

Gillis takes seven lessons a week at Fred Astaire and also practices on her own. During high school — Gillis attended Regional Center for the Arts, the Trumbull magnet school — these lessons were a way to combat anxiety and depression.

“High school was really hard for me, and dance was the one thing that got me to get to school,” Gillis said. “When I graduated I had no interest in college. That’s not how I like to learn — I’m more hands-on. It just felt natural to continue dancing.”

Through dancing, Gillis developed the confidence and poise that allows her to stay focused when she and her partner bump another couple or her dress gets caught underfoot.

“I’m pretty shy,” said Gillis, who also said she defies the bubbly dancer stereotype with her sarcastic, dry sense of humor. “It was so scary when I started out dancing and there were a bunch of people on the floor.”

Now Gillis sweeps competitions wearing her favorite custom dress, a long black number with emerald-green rhinestones, which she likes for its clean, understated look that allows her dancing to shine.

Though her instructors would say she’s strongest dancing Viennese waltz and foxtrot, she said, Gillis doesn’t have a favorite.

“If you have a good piece of music,” she said, “you can fall into it and just let go. That’s what I love.”

Gillis will perform at Holy Trinity Greek Greek Church, 4070 Upper Park Avenue, Bridgeport. The event is from 7 p.m. until midnight. Admission is $17. Call 203-374-7308 to RSVP.