The "Group Leader" was Jesse Pinkman's primary counselor at the rehabilitation clinic where he was previously a patient. After Jesse was released, he began attending regular group therapy sessions in a local church which were also lead by the leader from the clinic. His name has never been revealed.
On July 18, 1992, while drunk on vodka and high on cocaine, he killed his six-year-old daughter by accidentally hitting her with his truck.
Jesse first meets the Group Leader after he has been living at the facility for the past two months and attends an outdoor group therapy session at a campfire with several other recovering addicts.
When Jesse asks the group leader how he has accepted himself, he reveals he hit his daughter with his car, killing her. Jesse, still reeling from Jane's death, asks the Group Leader how can he not hate himself for what happened. The Group Leader responds that self-hatred and guilt stand in the way of achieving true change.
After not attending his meetings for several weeks, Jesse decides to return as he is feeling distraught about killing Gale. However, during the session, Jesse nearly breaks down and yells at Group Leader claiming that his philosophies on "accepting yourself" aren't true. Jesse then mentions the death of Group Leader's daughter and admits to the whole group that the only reason he came to the group meetings is to sell meth to them. He asks Group Leader if he's okay with that, to which the group leader responds, "no". Jesse then says, "about time", and leaves the session ("Problem Dog").
The Group Leader takes a calm, non-judgmental approach to leading discussions and emphasizes that those attending his sessions are there not to improve themselves, but to learn self-acceptance.