3. Jerry Gorsch
Jerry Gorsch (Steven Boyer) was bad news from the very start. He was the Assistant Deputy Commissioner in seasons 7 and 8, and he spent all his time trying to slash the budget of 51 by purchasing cheap equipment that put the lives of firefighters at risk.
Gorsch was the embodiment of the desk worker who didn't know anything about firefighting, which would have made him unlikable enough, but then it was discovered that he was also embezzling money from the department! Putting lives at risk and illegally profiting?
Take a bow, Jerry, you've earned your spot.