MacNeal is known for his extensive work with the Jim Henson Company. He has worked on Sesame Street since 1982. He also played the title character on Bear in the Big Blue House and its spin-off series Breakfast with Bear.
Many of MacNeal's roles with the Muppets are full-bodied puppets, such as various Snuffleupagus relatives on Sesame Street. He has doubled for Big Bird in various scenes over the years as well. In addition to performing, he has played an active role in hiring and training puppeteers for local Sesame Street productions in Japan, Mexico, South Africa, Jordan, Palestine, and India.
In the late 1980s, Noel MacNeal starred alongside Cheryl Blaylock on Eureeka's Castle. Blaylock played the title character, while MacNeal played her dragon sidekick Magellan. After Blaylock joined the cast of Oobi as Frieda the Foot, the writing staff specifically wrote an episode starring MacNeal and Blaylock together.
MacNeal played a character based on himself, named "Leon MacNeal," in every episode of the series Puzzle Place. He also worked on Between the Lions and Blue's Room, spent a stint as host for Sprout's The Good Night Show, and has puppeteered on more adult series including 30 Rock, Oz, Chappelle's Show, and Unbreakable Kimmy Schmidt. He is the resident puppeteer for Last Week Tonight with John Oliver. As a writer, he has contributed scripts for various PBS and Nickelodeon shows.