After starring as Maria in the 1996 National tour of West Side Story, Harriell made her Broadway debut on April 4, 1997 (after only 4 days of rehearsal) as Mimi in the Pulitzer Prize winning musical, Rent, starring opposite Adam Pascal. She went on to star in the Broadway musical Lennon, featuring the music of former Beatle, John Lennon; written and directed by Don Scardino. On November 11, 2008, she joined the cast of the 2008 Tony Award winning musical In The Heights, starring as Vanessa, opposite Lin-Manuel Miranda.

In 2006, Harriell auditioned for the Quentin Tarantino’s film Death Proof (part of the double feature Grindhouse.) Mr. Tarantino was so intrigued by Harriell’s “southern boy” characterization, that he rewrote the part specifically for her and renamed the character Marcy.

In December 2013, Lin-Manuel Miranda recruited Harriell to help him record demos of his songs for the Disney animated motion picture, Moana. Harriell’s outtakes of the songs More and More (Reprise) were included on the Moana Original Motion Picture Soundtrack.

Harriell is well known in the online sewing community through her popular blog oonaballoona, where she showcases her fashion designs and handmade wardrobe. She is the host of Re:Fashion,a show about sewing and fashion on NBC’s Bluprint. She has been a featured writer for magazines threads and Mollie Makes. In 2018 she was a guest on the Canadian sewing podcast Love To Sew where she talked about developing her confidence as a sewer.

Harriell can be seen in the 2019 motion picture Men in Black: International.