By age 21⁄2, he had the ability to identify cars by logo and body style, and was featured on the KHOU morning news in a segment on how to raise "smart kids.
"[14] Before working on Heroes, Rush appeared on Private Practice, and tailored several film credits, such as Blue Boy, The Journal, and Mindsight.
The same year he also appeared on Medium as Tanner Campbel, the boy in the banana costume, and on Criminal Minds as Ronny Downey.
[16] From 2017 to 2019, he gained prominence through his role as Cyrus Goodman, one of the two best friends of the title character on the Disney Channel series Andi Mack.
[11] Rush's performance was praised, and he is noted for having played the first gay main character on Disney Channel, and the first to have a same-sex love interest, TJ Kippen (Luke Mullen).
He voiced Toby in Netflix and DreamWorks Animation's The Adventures of Puss in Boots and Breehn on Cartoon Network's Clarence.
[22][23] Rush volunteered for the 2018 congressional campaigns of Beto O'Rourke, Ben McAdams, Harley Rouda, and Katie Porter.
[30][non-primary source needed] In April 2019, it was announced he would voice the titular character in DreamWorks Animation Television series on Universal Kids, Where's Waldo?.
[36] In February 2020, Rush opened up about his parents' divorce and his mental health issues in a Teen Vogue article.