I ain't cleaning that up.
Played as a cynical, sharp-toungued, hard-working, sassy but caring and responsible housekeeper, in her late 50s or 60s, Berta takes great joy in making fun of the Harper family for their faults as they amuse her. She often puts in good quips to conversations they are already having, ending or extending them. She strikes fear into the hearts of others simply by giving frowns. She does have a sense of decency and disgust, making her willing to leave the house when something is happening.
As of season nine, she is employed by Walden Schmidt to clean his house, giving her a reason to keep coming there.
Berta's Family life is often a topic on the show. She has three daughters, one brother named "Chick", a sister called Daisy and several granddaughters, all of whom are 'sleazy and easy,' in her words. She often brings her family to work (notably Daisy and granddaughter Prudence) and otherwise involves Charlie and Alan in their lives. When her youngest daughter Naomi gets pregnant, Berta leaves her with Alan and drags Charlie along to the suspected father's house to force him to help Naomi and their child. Alan dates Naomi with Berta's approval ("he isn't much but he's the best boyfriend Naomi ever had"), but Naomi eventually reunites with her child's real father. Prudence is the daughter of Berta's daughter Cheryl Ann.
Relationships with other people
Charlie Harper - Berta's late former employer and close friend. Berta is rather lazy and lax on the job, but Charlie is incapable of firing her out of respect, fear, and inability to run his home without her. When Charlie was dating a mean woman named Lydia, Berta quit, and not only did Charlie break up with Lydia, he agreed when Berta urged him to go to a sex-addicts' meeting. Charlie has claimed that Berta is like family to him, and he often seeks her advice. According to Chuck Lorre on the season 6 DVD, Berta and Charlie are probably best friends, although neither would ever acknowledge it. However, Charlie mentions more than once that he really loves Berta. Berta was sad when Charlie died, stating that he was the best boss she ever had. She disliked Alan moving back after Walden invited him to stay permantly as of "Nine Magic Fingers". He is succeeded by Walden Schmidt as Berta's boss after his death.
Alan Harper - Berta is annoyed by Alan. She quit shortly after Alan moved in, because he was 'a persnickety son of a bitch'. Alan apologized to Berta and she came back. Berta has nicknamed Alan 'Zippy'. She temporarily respected him when he dated her daughter Naomi, but only until they broke up. When Alan moved out of the house after Charlie passed away, Berta asks Alan for a hug, admitting that after everything they've been through over the years, they've been like family. This implies that Berta really does care about Alan, deep down. After his heart attack(s), Berta applies her rule of not making fun of people that can haunt her and stops calling Alan zippy.
Jake Harper - Berta dislikes Jake's complete lack of cleanliness, including his complete lack of care about cleanliness. Out of her extreme anger about how he leaves the bathroom, she trained him so well on the toilet seat that she claimed he could "pee through a Cheerio at 10 paces."
Evelyn Harper - Berta is the only one in the Harper household that does not fear Evelyn. She often makes sarcastic remarks instead of following orders issued by Evelyn, who simply calls her "the help."
Walden Schmidt - Berta's current employer, succeeding Charlie Harper in Season 9. After Charlie's death, Berta was left without a job for a short while. After Walden buys the Harper beach house, He initially re-hired Berta to work as a live-in but when Walden invites Alan to stay permanently, Berta resumes as a part-time housekeeper, rather than a live-in to avoid having to live with Alan and Jake. Berta was almost fired by Walden in "Mr. Hose says "Yes" because Zoey and Ava were staying at Walden's beach house for a week and she did not want to clean up after another child because she already did clean up after a child after Alan and Jake first moved in the beach house when Alan got kicked out and later divorced from Judith and when Charlie was alive and well.
Jenny Harper - Berta and Jenny get along well, she has not so far had any bad remarks towards Jenny. She has an orgy with Jenny, Walden, Jenny's friends and James Franco.
Rose - Berta is one of Rose's friends. Although Berta is not blinded by the fact that Rose has stalked Charlie, she still thinks he should of gave Rose another chance. In "Nice to Meet You, Walden Schmidt", Berta (along with Alan and Evelyn) suspects Rose had killed Charlie and no longer trusts her.