As between The Family sketches, the NBC version of Mama's Family, and the syndicated version, Thelma Harper went through many altering traits. On The Family sketches, Mama was always grumpy and trying to start arguments, as the sketches were full of bickering between she, her daughter Eunice Higgins, and her son-in-law, Ed Higgins. She was also quite senile, dependent, and behave more elderly on The Family. The NBC version saw the less easygoing version of Mama, as she was slightly naive, had an explosive temper and known for her wisecracking remarks. By the time the syndicated version came out, Mama became less of an elderly stereotype, was more relaxed, sometimes happy but also had many locutions including Good Lord!. Unlike the Family sketches, in the syndicated version, Mama didn't argue nearly as much with her family, but had a lot of control over them instead. Also, more than any other version, the syndicated version saw the most energetic, independent, and least senile version of Mama. For instance, Mama was involved in the Church Ladies League, dirty dancing, and various other activities in the syndicated version of the show. Mama could also be cheerful in the syndicated version, unlike The Family sketches.
In The Family sketches, Thelma and her late husband, Carl Harper, have five children: Ellen, Eunice, Phillip, Larry and Jack. In the "Eunice" television special, they have three children: Ellen, Eunice, and Phillip. In Mama's Family, Thelma also has three children, but the character of Phillip is replaced by Vinton. Thelma's husband Carl is usually portrayed in voice only (in the Eunice special he was voiced by the late Dick Clair), and is heard primarily from the main floor bathroom. Thelma is in her late 60s during "Mama's Family". Vicki Lawrence was in her 30s during this time and would not turn 60 until 2009.
In Mama's Family, Thelma lived originally with her sister, newspaper writer Fran Crowley. In the first episode, Vinton and his two children, Vinton "Buzz" Harper, Jr. and Sonja Harper, move in with Thelma after being evicted from their house. Vinton had just gone through a divorce from a woman named Mitzi, who fled to Las Vegas to become a showgirl. Vinton soon marries Naomi Oates, Thelma's next door neighbor, whom Thelma despises. Thelma becomes so enraptured and relieved to find out Naomi, Vint and the kids are going to move to Arionza to run a trailer park, that she consents to having them marry in her living room.
Following the wedding, they all return to Thelma's house to stay because Naomi's partner in the trailer park venture has absconded with every cent of Vint and Naomi's life's savings. There was never any trailer park in Arizona. And so Thelma gets stuck with Vint and his kids...and now Naomi!
Thelma's relationships with her grandchildren are different that those with her children. She gets along rather well with Buzz, since he isn't always worrying her into the grave, the way his older sister does and Thelma's own children had done when they were younger. In fact, Buzz seems to have a unique bond with his grandmother.
Thelma is best friends with her neighbor across the street, Iola Boylan, who is crazy about Vinton and agrees with Thelma that Naomi wasn't the right kind of wife for him. In fact, Iola thinks she would be Vint's perfect mate instead. Thelma and Iola often spend a great deal of time together, and Iola is often over for dinner when she isn't helping her eccentric and infirmed parents. Although they are best friends, Iola and Thelma do have their share of disagreements as well. Most of them are instigated by outside forces, but usually, they patch their differences and become friends again.
After Buzz and Sonja move out of the house for parts unknown, and Fran dies, Thelma is joined by her other grandson, Bubba. Her relationship with him is vastly different than the one she had with Buzz. Bubba is certainly his mother's son, and while not as contentious and selfish as Eunice was, he is just as headstrong and stubborn, though he matured as the series progressed. He makes no fan of his Uncle Vint and his Aunt Naomi when he is given Fran's old bedroom, relegating them to the basement yet again. However, given what Bubba has gone through, his father and his eternally selfish mother leaving him in Raytown while gallivanting off to Florida without even one word of good-bye, they were not about to begrudge him a bedroom.
Thelma has a very strong aversion to her grandchildren drinking alcohol. Although it's hypocritical, as she herself drinks a lot of beer. In one particular instance, when Bubba comes home drunk after several beers, she really lowers the boom on him. At first, nobody in her family understands why she is really punishing him hard; considering how often she drinks beer, until Iola explains about a really terrible situation with Bubba's mother, Eunice. During a Mother-Daughter banquet, Eunice showed up quite intoxicated. Then, during a song, Eunice and Thelma started having a violent argument on stage, during which Mama revealed to everyone present the circumstances under which Eunice was conceived. (Mama: "If your daddy hadn't gotten me as drunk as you are now, you never would have been!") That would perhaps explain just why Eunice and her mother don't get along to this day. Needless to say, Bubba swears off beer from now on.
Ironically, Thelma's embattled relationship with Eunice was not unlike the somewhat contentious relationship she had with her own mother. In her mind, Thelma's mother had no liking for anything Thelma did. In an episode where she deals with her own austere mother who haunts her for entertaining the idea of selling her brooch, Thelma calls her the same epithet that Eunice sometimes uses on her: "Old lady". At the end of the episode, Thelma's mother's haunting ends when Thelma sells the brooch, and then screams at her mother's apparition, "Get the hell out of my life!!!"
Thelma has held various jobs in Raytown. She works with Meals on Wheels; had a short stint as Mayor of Raytown; worked at a travel agency (for less than a day); worked at local grocery store, "Food Circus", to Naomi's disgust; went to night school; worked at a fast food restaurant. She wore many hats.
One of Thelma's life long dreams is to go to Hawaii. She gets her wish when she appears on Jeopardy!. While Thelma loses the main part of the competition, she does win a Hawaiian vacation as a consolation prize. The next two-part episode features Thelma, Iola, Vint, Naomi and Bubba's adventures in Hawaii.
As a former president of the CLL (Church Ladies League), Thelma has to deal with the ladies of the church, including the gossipy pastor's wife, Alberta Meechum, brazenly tries to break up Thelma and Iola's friendship by suggesting that Iola run for president of the CLL. (Ms. Meechum did this because Thelma had helped Alberta's husband spank their grandson, Little Eugene, for causing trouble for the Harpers and for kicking her husband in his sore leg. In her mind, Little Eugene was an angel, and helping to hurt him was a huge "no-no".) Neither Thelma or Iola wins and Thelma's eventual successor is a woman named Lolly Perdue, who wins because she was the only person big enough to separate the squabbling Thelma and Iola. Some time later, Lolly is the target of an impeachment attempt by Thelma and Iola, but they end up backing down when they discover Lolly is illerate. Thelma also has to contend with Reverend Lloyd Meechum, the man who married Vint and Naomi. She also babysat their grandson, a little demon named Eugene, with disastrous results.
Thelma was known for her somewhat uneasy relations with her neighbors, going back to when Naomi lived next door. Most of her neighbors wouldn't mind seeing her and her entire dysfunctional family move away and never come back. A large part of this animosity came about during an aborted attempt to knock down the neighborhood and replace it with a landfill. To Thelma's shock, the house she had lived in since she was married had once been a house of ill-repute where the town's founder, James A. Ray, died. Thus, it was made a Raytown historical landmark, to mayor Albert Tutweiler's chagrin, and her neighbors ire. They wanted a lot of money to leave that neighborhood and lose Thelma as a neighbor, but it was not to be. Even Iola was irate.