She took numerous singing, dancing, piano and acting classes, and one of her teachers put her in touch with a New York City talent agency, which signed her.

[4] Sonenclar began her professional career in 2006 in a stage adaptation of The Night of the Hunter, at the New York Musical Theatre Festival, in which she played the lead role of Pearl.

Sonenclar made her television debut as Gilda Flip on PBS,[5] the newest Prankster in season three of The Electric Company, produced by Sesame Workshop.

[11][12] In 2012, Sonenclar auditioned for the second season of The X Factor USA with the song "Feeling Good" by Anthony Newley and Leslie Bricusse (famously covered by Nina Simone among others).

[13] After her successful initial audition, she advanced through the first day of the "Bootcamp," stage of The X Factor where she sang "Pumped Up Kicks" with Beatrice Miller.

[20] In August 2013, she performed in New York City at the Best Buy Theater in Times Square as part of the Stand Up for a Cure 2013 Concert Series.

[21] Sonenclar appeared in an episode of Law & Order: Special Victims Unit, "Dissonant Voices", which aired in November 2013, during the show's fifteenth season.

[25] She gave a concert at Provident Bank Park in Pomona, New York, in July 2014, where she performed three original songs, “Aliens”, “Weekend” and “Everybody’s Watching”.

[26] On May 29, 2014, Sonenclar was ranked fifth by Fox Weekly on their list of Most Influential X Factor USA Contestants for her audition performance of "Feeling Good".