He won the Annie Award for Outstanding Achievement for Voice Acting in a Feature Production for his vocal performance as Hogarth Hughes in the animated film The Iron Giant (1999).

Marienthal was born on March 6, 1986, in Santa Monica, California, to Penny and Joseph.

[4][5] Marienthal graduated from the private East Bay French-American School in Berkeley.

[7] Marienthal's career started in Bay Area stage theater work, performing in Missing Persons, The Cryptogram, Hecuba, A Midsummer Night's Dream, Every 17 Minutes the Crowd Goes Crazy, and The Life of Galileo.

[citation needed] Marienthal also voiced the character Robin (Tim Drake) in the Static Shock episode "The Big Leagues", and reprised his role in Batman: Mystery of the Batwoman.