- First big break was writing and performing humorous essays on a local Pittsburgh show, PM Magazine, in the early 1980s.
- Appeared on Star Search, where he lost to Sinbad.
- Younger brother Jimmy has managed the careers of several major comedians, including Jim Carrey, Will Ferrell and Gary Shandling.
- His two sons are named for Holden Caulfield, the protagonist in Catcher in the Rye, and legendary actor Marlon Brando.
- Penned a series of books based on his signature stream-of-consciousness-style monologues, starting with 1997's Rants.
- Mocked the annual Presidential address on Comedy Central's State of the Union: Undressed, but then sat in the House gallery as a guest of President Bush for the 2004 State of the Union.
- Launched his own radio program, The Dennis Miller Show, for Westwood One radio network in March of 2007.
- In 2008, became a spokesperson for USA Cares, a nonprofit organization that provides financial assistance to military families.
- Appears periodically as a commentator on Fox News political talk shows.