He is a member of the Lumby family, who created and produced the 1980s Canadian children's television series, Size Small, where he performed as various characters and a puppeteer.
Lumby played "Winston Rothschild III", the septic tank and sewer technician character on The Red Green Show and Duct Tape Forever.
Skatoony which was originally developed in the UK debuted in Canada in 2010 and Jeff voices one of the new additions to the North American version, Studio Executive and Producer, Charles La Puck.
Jeff has provided animated voices to many projects over the years, including the Mad scientist role of Professor Tomoe in the Cloverway dub adaptation of the Sailor Moon anime series in season three; his sister, Lisa Lumby-Richards (who appeared on Size Small as "Grandma Gussie"), was a screenwriter for the adaptation.
On July 5, 2010, Lumby became the interim morning show host on sports radio station The FAN 590 in Toronto after the station fired its long running morning show duo of Don Landry and former Toronto Maple Leafs General Manager Gord Stellick.