Her interest in puppetry began when she received a pig puppet as a prize for winning a local essay contest in Oakland, California. Following her studies at Oberlin College, she interned at the Puppetry Arts in Atlanta, Georgia. In the early 1990s, she was employed with the Jim Henson Company where she performed characters for the children's TV series, Sesame Street.[4] Some of her characters are Sherry Netherland, the owner of the Furry Arms Hotel, and Phoebe, a member of the Monster Clubhouse, from 2001 to 2003.
Non-Muppet productions in which she has performed include the horror-humor TV series, Buffy the Vampire Slayer. On the show, she performed as a demon puppet in As You Were and a living mummy hand in Life Serial. After the series ended in 2003, Dinnean performed the puppet-like character of Angel in the episode Smile Time along with Drew Massey.