DeMayo met Hilari Scarl when he was working at the National Theatre of the Deaf which led to his being cast in See What I'm Saying.[4] He created a one-man comedy show about his life called Me Hear NONE which he performed at Philadelphia's Independence Starts Here festival in 2007 and then toured with.[5] He has worked as an ASL consultant and as a theater interpreter at Juilliard.[6]
DeMayo has created a 30-episode 10-DVD educational series of videos about sign language and deaf culture called Sign With Robert created for classroom use. In 2017 he worked with Giphy to create a series of 2,000 animated GIFs of him performing ASL words and phrases to help others learn sign language.[8] The GIFs have been viewed 2.4 billion times as of February 2022.[9]