Frieda was first introduced to Charlie Brown by Linus on March 6, 1961. She served as a major part of the comic strip for a brief period of time and appeared in the TV specials. Her first television appearance was in A Charlie Brown Christmas in 1965.
In her early appearances in the strip, Frieda is presented as a chatter box. She sits behind Linus in class, but due to her constant talking, Linus claimed not to have heard a word that their teacher has said all year.
Frieda is very proud of her "naturally curly hair". She manages to bring up the topic of her hair in every conversation, which is shown to annoy the people around her. In turn, Frieda believes the other girls are jealous of her hair and becomes disappointed when a girl says otherwise. Frieda also believes people expect more from her because she has naturally curly hair.
Frieda's last speaking role in the strip was on March 20, 1975, but she continued to appear as a background character until November 22, 1985. Frieda also continued to make appearances in both the animated Peanuts specials and the Saturday morning series The Charlie Brown and Snoopy Show - even being mentioned in the lyrics of the latter's theme song. She is also featured as an unseen character in the musical You're a Good Man, Charlie Brown, having been mentioned several times and yelled to at one point.
Unlike Lucy, Patty, and Violet, Frieda is usually a lot nicer to Charlie Brown and seems to be mindful of his feelings. Although she becomes angry with Charlie Brown on a few occasions, she never teases him or puts him down (except for rare moments in the Peanuts television specials). She eventually joins Charlie Brown's baseball team as an outfielder, but refuses to wear a baseball cap because it would hide her naturally curly hair. She seems to be one of the few characters in the neighborhood that Charlie Brown feels confident enough to stand up to. In one strip, Frieda is badgering Snoopy about chasing rabbits and Charlie Brown simply tells her to mind her own business.
Linus was the first character in the comic strip that Frieda met. She is also his classmate and sits behind him in class. From the start of Frieda's appearance in the strip, Linus is seen taking her around the neighborhood and introducing her to the other kids. Not much is shown of their friendship beyond those strips that introduce her, but even early in their relationship, they seemed to look out for each other. In one strip, when Frieda unintentionally hurts Lucy, Linus begs his sister not to slug her. Frieda is one of the few characters who does not see Linus' need for a security blanket as a bad thing, for which he is so grateful that he kisses her hand.
Out of all the characters in the strip, Frieda has the most trouble getting along with Snoopy, to whom she frequently accuses of being "lazy" and "useless." She has strong preconceived notions of what a beagle should be doing with its time; she insists that Snoopy become a working dog and a hunter (especially a hunter of rabbits), instead of spending so much time sleeping on top of his doghouse. She often comes over and tries to goad Snoopy into chasing rabbits with her, either by threat or persuasion. Snoopy is always reluctant to take up Frieda's suggestion. If he does consent to hunt, he will either "sandbag it" and only pretend to look for the rabbits, or if he does find rabbits, he will instead frolic and play with them once he is out of Frieda's sight. In one strip, Frieda reports Snoopy's behavior to the "Head Beagle" in a fit of frustration, which leads to him being found guilty of not meeting his rabbit quota. The other children in the neighborhood get angry at Frieda for turning him in. Frieda even buys a cat (Faron) as a way of motivating Snoopy to get over his laziness.
Frieda was able to make Lucy jealous by leaning on Schroeder's piano. Schroeder seems to dislike her as much as he does Lucy, since she also does not know who Beethoven was (even though Frieda claimed that she was hanging around Schroeder because she was a music lover). In The Charlie Brown and Snoopy Show, Frieda comments to Lucy that Schroeder is not very friendly. When Frieda is about to kiss Schroeder during his piano playing, she is surprised to find that she has instead kissed Snoopy on the lips. On another occasion, Lucy (with encouragement from Schroeder) actually gets into a physical altercation with Frieda. Schroeder eventually reaches a breaking point in the strip when Frieda makes a remark about Beethoven, causing him to knock both Lucy and Frieda off his piano.
Almost as soon as they are introduced, Frieda's relationship with Lucy had gotten off to a rocky start when she brings up the subject of her naturally curly hair. Lucy becomes visibly offended by this, so much that Linus (upon introducing her to Frieda) feels it necessary to beg Lucy not to slug her. Despite Frieda's faux pas, the two girls eventually became friends. When they are playing baseball for Charlie Brown's team, they often spend their time in the outfield chatting instead of paying attention to the game.
- In the TV special It's Spring Training, Charlie Brown, Frieda is said to be Leland's sister, but this is never mentioned in the strip, and therefore, can not be considered canonical.
- She is one of the many characters to appear in the game Snoopy's Street Fair, in which she owns a "cuddle a cat" booth, which is a reference to her cat, Faron.