"[7] Slater graduated from Georgetown Day School in Washington, DC, and studied drama at Vassar College in Poughkeepsie, New York.

[12] In December 2015 he joined the Delaware Theatre Company in Wilmington, acting in Barry Levinson's play Diner, directed and choreographed by Kathleen Marshall.

In 2016 Slater was cast in the lead role SpongeBob SquarePants in Kyle Jarrow's musical of the same name directed by Tina Landau at the Oriental Theatre in Chicago.

[17][18] Between 2018 and 2019 he appeared in a few episodes of television series, including Law & Order: Special Victims Unit, Murphy Brown, Instinct, and The Marvelous Mrs. Maisel.

[19] Between 2021 and 2022 he starred in the musical Assassins with the direction of John Doyle at the Lynn F. Angelson Theater in New York, playing Lee Harvey Oswald.

[21] From March to April 2022, Slater originated the role of Max Weinbaum in the play Good Night, Oscar at the Goodman Theatre in Chicago.