On November 11, 2008, she joined the cast of the 2008 Tony Award winning musical In The Heights,[4] starring as Vanessa, opposite Lin-Manuel Miranda.

On television, Harriell has been a Series Regular on NBC's Ed, HBO's Nurse Jackie and the CBS courtroom dramedy Queens Supreme.

[5][6] She has been a guest star on numerous television programs, including: NCIS, Law & Order, Elementary, Royal Pains, Beauty & the Beast, Gone and Search Party.

[9] In December 2013, Lin-Manuel Miranda recruited Harriell to help him record demos of his songs for the Disney animated motion picture, Moana.

In 2022, Harriell was tapped as star vocalist by Mark Morris in his latest evening-length piece "The Look of Love" based on the classic Burt Bacharach, Hal David, Dionne Warwick hit songs.