The first villain who appeared in the TV-series, Totally Spies!, his first appearance being in the pilot episode, "A Thing for Musicians."
Before becoming a villain, Sebastian was a big-time professional guitarist. But a freak pyrotechnic accident severely injured the left side of his face, completely destroying his left arm in the process, which ultimately rendered Sebastian unable to play the guitar (due to being a left-handed guitarist).
After his career as a musician ended, he became a "reckless" music producer/manager, eventually becoming the manager of fledgling rockstar, Ricky Mathis. Sebastian planned to play hypnotic music during Ricky's music concert in order to hypnotize the crowd into attacking the world's governments. Fortunately, the spies—Sam, Clover (who got hypnotized in the process) and Alex—confronted Sebastian at the concert and foiled his plans, forcing him to attempt an escape in his personal helicopter.
The spies turned Sebastian's own trick against him by targeting the helicopter with a wind tunnel hair dryer pushing the helicopter into the transmitter playing the hypnotic music, enabling the capture of Sebastian.
Sebastian's next appearance was in "Stark Raving Mad," where he escaped prison and was seeking revenge on Sam, Clover and Alex by way of destroying the places they favored most: 1.) A roller disco (for Alex), 2.) An art museum (for Sam) and 3.) The Beverly Hills Mall (for Clover). Sebastian attempted this through sabotaging local raves with hypnotic music that made people go berserk and start riots. Sebastian final place of destruction would've been the spies' high school, Beverly Hills High School, but they were ultimately able to stop him and send him back to prison.
- He was featured in an episode of The Amazing Spiez, a spin-off series to Totally Spies!.
- Sebastian's the first villain of the TV-series, but the spies' first villain is technical Fabu from the movie.