Garrett Xander Lambert is a student at Greendale Community College. He is primarily involved in science classes, though he is also active in the AV club and took an acting course once. He is a highly excitable young man who is easily flustered and is one of the more colorful students who attend the school. Several rallies have been held by the Greendale students dedicated to Garrett in order to "save" him. His first appearance was in the Season One episode "Social Psychology". He is portrayed by actor/comedian Erik Charles Nielson.
Garrett was a member of Professor Ian Duncan's lab study and took part in observing a group of students who unknowingly where testing the theory of "The Duncan Principle". Along with the rest of Duncan's students, Garrett spends over 26 hours waiting in vain for Abed to have an emotional breakdown. With Abed seemingly unaffected by the principle, Garrett tells Duncan he has to go forced to go attend his other classes. Before he goes the professor insults him. He participates in the 2009 Paintball Assassin game but is eliminated early. He manages to talk to Jeff briefly about the competition before being shot again by Leonard. On the last day of the school year, Jeff makes his way across campus to the library and notices Garrett lying on a bench "chillaxing".
in the study groups second year at Greendale, Garrett is first seen participating in the "Troy and Abed in the morning" show as the weatherman. He also accidentally gets nominated for student president when he tried to get ice cream and stepped into the wrong line. He is on the production crew along with Pavel for a documentary Abed is filming involving Pierce bequeathing things to the study group. He takes an acting class taught by Professor Sean Garrity that Troy and Britta also attend. He is asked by Garrity to recall a past trauma in order to access pain that he could use for a realistic performance. He tells the class about being bullied in the playground when he tried to go on the swings. The professor assumes this happened in his childhood but is or reacted when Garrett tells him that it happened this morning. He participates in the paintball war between Greendale and the City College Storm Troopers lead by Dean Spreck. He disrespects Annie's idea at a meeting of the student rebel alliance claiming that he won't do what a girl says because they never talk to him. He joins Troy's commando squad and helps set up a trap for the City College Storm Troopers inside the library. Unfortunately, he gets stuck in the air vent of the study room cutting off their escape route. He is later seen celebrating the Greendale's victory over their rival along with other students.
"For A Few Paintballs More": Garrett joins the Greendale alliance against t the City college invaders in a paintball war. He ends up ruining the escape plan of his squad by getting stuck in the air vent.
Garrett acts as moderator for the Model U.N. showdown between Annie Edison's Blue Model U.N. and the Red Model U.N. led by Annie Kim . Annie and a student named Kim tell Jeff about several "Save Garrett" rallies that were held in his honor. He helps Troy build his blanket fort and informs him that they are more than 2000 square feet shy of beating the current Guinness world record holder of the world's largest blanket fort but Abed's pillow fort is in the way. He is later seen in the study room showdown between Troy's blanket fort citizen's and Abed's Pillow fort dwellers. He later takes part in the final battle between the two forts in the cafeteria. In a flashback by the study group recalls an incident earlier in the year when Ben Chang was trying to see if Garrett had precognitive abilities and an imagined flashback saw him as a psychologist observing the study group in an insane asylum.
Garrett returns for a fourth year at school taking part in a demonstration led by The Germans. They were all protesting the group's hogging of Group Study Room F. A flashback reveals that in the study group's second year they prevented both Garrett and Todd from using the study room despite them having reserved it in advance. This took place when the group was strip searching in order to locate Annie's missing pen. He later assists Abed in the filming of his documentary of Greendale's attempt to secure funding for research into "Changnesia". As a drama student, he is asked along with his classmates (including Vicki) to portray rambunctious and unruly P.E. students for a teaching lesson in Shirley and Troy's Physical Education Education class. He gets into the part by scratching himself repeatedly and playing the role as if he has Eczema. His character and Vicki's get into a slap fight which is immediately stopped by Shirley who establishes her coaching authority in the scenario over all the "students". When it's Troy's turn to be the coach he loses control of the simulated situation immediately and gets shoved into a locker by both Garrett and Vicki. Towards the end of the school year he attends Jeff's graduation ceremony in the study room. He is sitting on the "bride's" side of the attendants along with Todd, Vicki, Magnitude, Neil and Leonard.
In his fifth year at Greendale, Garrett was trying to open his locker when Neil passed by and reminded him about free crackers at the reopening of Shirley's Sandwiches. After he unlocked the combination,molders fell out and he bent over to pick them up. Someone suck up behind Garrett while he was distracted and stuck a quarter down his exposed derrière. Garrett froze when this happened and when the shock wore off he ran to the cafeteria to warn everyone that the "Ass Crack Bandit" had returned.
In Garrett's sixth year at Greendale, he and a number of students were involved in a major accident on school grounds. While Garrett was inside the cafeteria, the roof suddenly collapsed. Garett was in the lunch line when plastic discs started raining down on everyone. The cafeteria was flooded with over thirty years worth of frisbees and Garrett was forced to ride the wave out into the hallway. He found minor fame acting as a stand on for a CGI character called Glip Glop when he takes part in Abed's production of a low budget sci-fi film. Along with a group of other students he helped the Save Greendale Committee pull a con on the new Grifting professor. He performed a stand up comedy act in order to promote a show he is co-starring with Vicki in. Garrett and his girlfriend Stacy get married only to have the ceremony and reception almost ruined by the committee when he finds out he's related to his bride.