Mari Jones is a workaholic person who loves helping people around her. From giving free rides to giving away huge amounts of money, she doesn't actually care if it is to help other people even just a little. Her soft voice and flirtatious personality makes her a constant target of the men in the city's cheesy pickup lines; which amuse and bother her at the same time. Since she is serious on her job and being part of High Command, MJ is addressed, mostly by Khloe and Bambii, as "MOM" whenever she is on shift with them.
After her father died during a call as a firefighter due to a lack of ambulances to transport him to the hospital to get treated, MJ fell into a five year depression stage before deciding to move forward and become an EMT to prevent what happened to her from happening to other people. Moving to Los Santos and getting started as a volunteer at Pillbox Medical Center, she started to understand the love and passion her father had for his job and the love for the community which made Mari Jones get more into EMS.
After four months she went up on the EMS ladder going from a simple volunteer to Captain. Her hard work and love for saving people's lives made her the perfect candidate to become High Command on the EMS front lines.