[5] After being seen at a showcase in New York, directed by Peter Seidman, Parrish was offered professional representation and went on to guest star in several television shows and appeared in the film Sleepover (2004).

Part of the main ensemble cast, Parrish portrayed the role of the older Botwin son, Silas.

Following filming of Weeds fourth season, Parrish joined the cast of the Tony Award-winning Broadway musical Spring Awakening at the Eugene O'Neill Theatre in New York City.

[7] He made his Broadway debut on August 11, 2008, as the replacement for the lead role of Melchior Gabor for which he received critical acclaim.

In Freedom Writers, Parrish played Ben Samuels, the only white student in a California high school class.

In 2017, Parrish was cast in the recurring role of Clay Haas in the second season of ABC's thriller series Quantico.

[17][18] In 2022, Parrish was cast in the Hulu mystery thriller series The Other Black Girl, a television adaptation of the 2021 novel by Zakiya Dalila Harris.

At first, Guessing Games was only available for sale in the lobby of Godspell’s home at the Circle in the Square Theatre, but with a bigger release to follow.