DogLion didn't have a permanent performer. Of the big monsters, only Sweetums (Richard Hunt, now John Henson) and Thog (Jerry Nelson) had a single performer. The others were all flexible. Actually he only had dialogue in three episodes, all in Season Two. Here's the list of all the people who did DogLion in speaking parts on TMS:
#33 Madeline Kahn: Jerry Nelson
#35 Dom DeLuise: Frank Oz
#48 Cloris Leachman: Jim Henson
Also, Dave Goelz played in on The Cosby Show from the midnight snack induced nightmare episode.
Side commentary, only Sweetums and Thog seemed to have set personalities among the big 8 (Sweetums, Thog, DogLion, Timmy, Big Mama, the Mutations). This is probably due to the fact they didn't have multiple performers. It's part of the reason I favored a Thog figure over a DogLion figure. Sweetums and Thog have characters that can be easily and consistently described, but the rest change. Commentary over.
David "Gorgon Heap" Ebersole