Within a year, Steuer had received a minor guest-starring role on the television series Day by Day. In 1990, Steuer was cast as Alexander Rozhenko in the Star Trek: The Next Generation episode “Reunion”. Although a number of young children auditioned for the role, Steuer was the only child able to sit still for the three hours it took for the make-up department to cast his Klingon facial prosthetics. The ability to be still for a long period of time won him the part. The producers of the series sought him out a year later to reprise the role. However, Steuer had only grown half an inch in height and, at six years old, did not have a deep enough voice. So the producers cast actor Brian Bonsall, who was more than two years older, as Alexander. Steuer later said he was very upset at the part being recast.

During his time on Grace Under Fire, Steuer was cast in the 1994 comedy film Little Giants. He co-starred alongside 13-year-old Sam Horrigan. Horrigan replaced Steuer in the role of Quentin Kelly after Steuer left Grace Under Fire.

Steuer eventually moved to Denver, Colorado. In 2003, he and several other local musicians formed the glam punk band Kill City Thrillers. Steuer performed as lead singer for the band under the name Jonny P. Jewels. Within a few months, the band changed its name to Soda Pop Kids, and about 2005 the band and most of its members moved to Portland, Oregon. The band dissolved in November 2009.

In March 2015, after several years working as a bartender and server, Steuer partnered with chef Sean Sigmon to open Harvest at the Bindery, a vegan restaurant located in Portland.

Steuer died from a self-inflicted gunshot wound on January 1, 2018, aged 33, in Portland, Oregon. Upon Steuer’s death, the restaurant closed permanently.