Gale is the first person to be killed by Jesse, and the last person to die in Season 3, although his death wouldn't be confirmed until the beginning of Season 4.

Did Jesse kill Gale in breaking bad?

Gale Boetticher

Once Walt realized that Gus intended to replace him and Jesse with Gale once he mastered Walt's recipe, Walt ordered Jesse to kill Gale and make them invaluable for producing their blue meth. Cause of Death: Gale was shot by Jesse.

Did Victor or Jesse kill Gale?

Jesse shot and killed Gale at his apartment before Victor arrived to stop him. In the Breaking Bad season 4 premiere, "Box Cutter," Walt and Jesse were held hostage so that Gus could punish them for their actions.