|Chantelle Cahill is the mother of Mark Cahill, a high school student who took classes part time at Greendale. She enjoys plastic surgery, Bikini waxes and drinking Vodka early in the day. Her son Mark antagonized Jeff Winger with whom she had a brief fling. Chantelle's first appearance was in the Season One episode "The Art of Discourse".|
In the study group's first year at Greendale, Chantelle Cahill picked up her son Mark along with his friends Kelly and Scott. The teenagers had all just finished taking extra credit courses at the community college. She was unaware that she had been observed by Jeff and Britta. They had been who had spent the last few days being mercilously mocked by her son and were looking for revenge. The next morning, once Chantelle dropped off the three teens, Jeff approached her under the guise he was on a routine excercise run. He asked her if she had a spare sports drink and a smitten Chantelle handed him a bottle. The two flirted as Britta observed them from behind a bush hedge. Not long afterwards, Jeff was in the cafeteria with Chantelle massaging her shoulders.
Mark and his friends interrupted thier canoodling after Britta pointed it out to him. Chantelle was upset until her son pointed out she was being used by Jeff to get payback for being "pwned" by Mark all week. Chantelle saw through Jeff's act when he feigned innocence and rejected him. Jeff decided to give up and tried to walk away in order to be the better man. As he left, Chantelle blasted Jeff by saying losers like him will always be beaten by winners like her son. Jeff then changed his mind and challenged Mark to a taunting competition. Mark and him went at it for twelve minutes and they were eventually joined by Kelly, Scott and Britta. Chantelle herself stayed on the sidelines encouraging the teens to win.
Just as Jeff and Britta seemed to run out of steam they were saved after Shirley and Pierce came to their rescue. Together they pantsed Kelly and Mark which stopped them from taunting. Jeff and Britta won by default which Mark immediately protested. Chantelle told him it was over and to accept his defeat instead of adding to his (and her) humiliation by complaining about it. She led Mark and his friends away as the study group gathered to celebrate Jeff and Brittas "victory". However, Mark and his friends quickly returned and instigated a huge food fight in the cafeteria after throwing food at Troy. Its revealed that sometime afterwards Jeff and Chantelle slept together twice ("The Art of Discourse").