Evelyn Nora Harper is Charlie and Alan's conceited and self-centered mother and Jake's grandmother. She expresses a superficial fondness for her sons and grandson when she's obligated to, but rarely lives up to her act of a devoted, but misunderstood, matriarch. Her sons and grandson generally return the favor and go out of their way to avoid interacting with her on most occasions. And refer to her as cold, insufferable, destructive--and mostly, unnessicary for anything.

Her wide-ranging sex life is a recurring gag throughout the series. The family frequently refers to her as "the devil." Charlie keeps her phone number on speed dial as "666. Cute, huh?" and when asked if he knew her favorite perfume, he asked a store clerk if she carried "Chanel No. 666". Once she showed up in a black cloak and Grim Reaper-like staff. Alan asked "Who is it?" and Charlie replied, "It's death." Alan then called out, "Hi, Mom!" Her latest romance ended disastrously when her new husband (Teddy) had a heart attack while sleeping with his "stepdaughter," only for the police to reveal that Teddy was a con artist who had planned to steal all of Evelyn's money and share it with the young woman, who was his much younger partner and lover.