Born and raised in Harlem, New York, she began her career in the music industry as a backing vocalist for Christina Aguilera, Alicia Keys, John Legend, Leona Lewis, and Usher.

Allen's maternal Bermudian grandmother was one of the first people of African descent to attend Juilliard School of Music.

Sasha has also toured with Alicia Keys, Leona Lewis, and John Legend, performed with Usher and David Bowie, and recorded with Celine Dion.

Allen's television work as a vocalist with musical director Rickey Minor garnered her performances with Jessica Simpson, Patti LaBelle, Yolanda Adams, Fantasia, and Clint Black.

[clarification needed] Returning to reality TV, Allen was selected as a participant for the fourth US season of The Voice.

In the battle round she competed against Amber Carrington, who Adam would end up picking, making Sasha available to be stolen.

Allen would be the final remaining member of Team Shakira, and the first stolen contestant on The Voice to advance to the semifinals.