From Disney's Hollywood Studios Wiki
The Swedish Chef is a Muppet Character, characterized by his Chef Attire, and his mock-Swedish accent. He rarely, if ever, speaks actual Swedish, but instead a garbled language with a few English words, and a large amount of the sound "bork" (Example: "Toda we maka de Fishy Chowder").
 Studios Reference
On the side of Muppet*Vision's building, there is an add for his company that says "The Swedish Chef's Editing and Catering: From Quick Cuts to Cold Cuts."
He was in video footage in Here Come the Muppets.
The Swedish Chef made several appearances on The Muppet Show.
He has appeared in every Muppet Movie to date, but mostly brief cameo appearances. For example, he is featured in "Muppet Treasure Island" on an island populated mostly by pigs, wearing a pig nose, which prompted a tomato he was cooking to comment "How else were we supposed to get him in the movie?"
In the "Muppet Movie," the Swedish Chef ran the camera, which most likely inspired him running it again in Muppet*Vision 3-D.
 Preformed By
The Swedish Chef was performed by Jim Henson until his death, including voicing the animatronic in Muppet*Vision.