Nat Mongioi was the set decorator for Sesame Street from its first season (1969) through Season 38 (2007), as well as its many specials and home video productions. Mongioi has received many Daytime Emmy Award nominations for Outstanding Achievement in Art Direction, Set Decoration and Scenic Design, and won the award in 2005.
Mongioi has also worked on The Electric Company, 3-2-1 Contact and Square One TV.