In 2003 Dinello co-authored the novel Wigfield with Sedaris and Colbert, which they promoted by creating a traveling play.
Most recently, Dinello has made guest appearances on Colbert's show The Colbert Report as Tad, the building manager. The character is often berated by Colbert, who forces him to do dangerous things. Dinello has made at least five appearances on The Colbert Report, including a tumbling act with Colbert and their Strangers costar Sedaris in July 2006. After a prolonged absence, Dinello returned as Tad on 12 July 2011 to help Colbert interview activist Dan Savage.
Dinello was also a writer, producer and director for the Strangers with Candy film, which was released in July 2006. In January 2009, Participant Media announced it would produce Dinello's next film, Mr. Burnout (about a burned out teacher seeking to rekindle his love of teaching).
He was one of the main cast in the show Exit 57, also starring Sedaris and Colbert. He also appeared as Mr. Rooney in the film Be Kind Rewind, alongside Jack Black and Mos Def.
Dinello recently directed the Nickelodeon original movie Gym Teacher: The Movie, starring Christopher Meloni and Amy Sedaris.
Dinello can be seen with Amy Sedaris in the "Mummified Hand" episode of the Science Channel show Oddities.
On the July 12th, 2011 episode of Comedy Central's "The Colbert Report", Dinello appeared briefly as Colbert's "heterosexual accountibility-buddy" and potential companion to a gay wedding.