* Alan Harper: Charlie's older brother, a failed chiropractor who moves in with Charlie after his divorce.
* Jake Harper: Alan's son, who lives with Charlie and Alan after his parents' divorce.
* Berta: The Harpers' housekeeper, a no-nonsense woman who often dispenses wisdom and advice to the other characters.
* Evelyn Harper: Charlie and Alan's mother, a wealthy and eccentric woman who often visits the Harpers and causes chaos.
* Judith Melnick: Alan's ex-wife and Jake's mother, a controlling and demanding woman who often tries to interfere in Alan and Jake's lives.
* Walden Schmidt: A billionaire internet entrepreneur who moves in with Alan and Jake after Charlie's death.
* Louis: Walden's son, who moves in with Walden after his mother's death.