Jim Henson was a puppeteer.
Jim Henson . While he was a freshman at the University of Maryland , College Park , he created Sam and Friends , a five-minute sketch-comedy puppet show that appeared on television . He won fame for his creations , particularly Kermit the Frog , Rowlf the Dog , and Ernie , and was involved with Sesame Street for over 20 years . He also had frequent roles in Muppets films such as The Muppet Movie , The Great Muppet Caper , and The Muppets Take Manhattan , and created advanced puppets for projects like Fraggle Rock , The Dark Crystal , and Labyrinth . Kermit the Frog is a Muppet character and Jim Henson 's most well-known creation . Henson originally performed Kermit until his death on May 16 , 1990 ; Steve Whitmire has performed Kermit since that time .