Marcie

Marcie wears round glasses with opaque lenses and wears her dark brown (sometimes black) hair in a short bob style.[3] She also wears an orange t-shirt (colored red in The Peanuts Movie). She and Peppermint Patty were the only girls in the strip to wear a t-shirt and shorts (although Lucy and Sally wore pants during the winter in the 90s’ strips, and Eudora wore pants regularly).

Marcie is best friends with Peppermint Patty, constantly addressing her as "sir" (she called her "sir" in her first line in the strip). Originally, Peppermint Patty keeps telling Marcie to stop calling her that, but eventually grows accustomed to it. Initially, Peppermint Patty addresses Marcie as "dorky" and, when talking to others, refers to her as "my weird friend from camp". Because of the close friendship between Marcie and Peppermint Patty, some have inferred a romantic relationship between them.[4][5]

Marcie is in many ways the opposite of Peppermint Patty: where Peppermint Patty is more comfortable playing sports, the well-read Marcie prefers a quieter, more studious existence. Although Marcie repeatedly professes her dislike of sports, particularly baseball, she will occasionally take part in whatever sport Peppermint Patty is involved in at the time, though more often than not, Marcie, upon showing her lack of athletic prowess and lack of knowledge of the game, usually only succeeds in frustrating Peppermint Patty.

Her ineptitude at sports was not consistently carried over in the prime-time animated TV specials in which the Peanuts cast was featured. In the special You're the Greatest, Charlie Brown, she proved quite capable on the athletic field, even winning the decathlon for the school. However, Schulz did not consider these to be canonical.

Like Peppermint Patty, Marcie also has an unrequited crush on Charlie Brown (whom she usually calls "Charles", or occasionally "Chuck", as Peppermint Patty does); she once confessed a fondness for Charlie Brown and would be willing to marry him if he asked her. While Peppermint Patty is more likely to flirt with Charlie Brown and play mind games with him, Marcie is more frank in her admissions of her feelings, and often asks Charlie Brown in plain language if he likes her. As he does with Peppermint Patty, Charlie Brown often responds to Marcie's inquiries by trying to evade the issue -- though it appears as if he has feelings for her -- which more than once has made Marcie so angry that she kicked him in the shins in frustration. Another time she consoled him for losing the decathlon in You're the Greatest, Charlie Brown by calling him "a good athlete and a true gentleman" and lifting her glasses to wink at him (making it one of the few times her eyes were visible). She has on more than one occasion kissed Charlie Brown on the cheek. The first time was in the 1973 special There's No Time for Love, Charlie Brown, but she only did it so Charlie Brown could pretend that it was a goodnight kiss from Peppermint Patty. She also kissed him in the specials Happy New Year, Charlie Brown! (1986) and He's a Bully, Charlie Brown (2006), and in "The Wright Brothers" episode of This Is America, Charlie Brown. She also kissed him in the strip in the "Lost Ballfield" story arc in 1982.

Marcie and Peppermint Patty also share a crush on a boy named Pierre in the animated movie Bon Voyage, Charlie Brown (And Don't Come Back!!). Although Marcie is the one in whom Pierre seems to express interest, Peppermint Patty misreads the signs and seems convinced that Pierre likes her instead.

Though Marcie is usually slow to anger, she can occasionally lose her temper when provoked. Case in point, in a sequence from July–August 1973, when she reluctantly joins Peppermint Patty's baseball team, she becomes the target of a male teammate named Thibault (pronounced TEE-bo), who constantly follows her around tormenting her with chauvinistic insults until she ultimately slaps him senseless. Thibault completely ignored the fact that Peppermint Patty was also a girl, though given her tomboyish nature, he may have simply been unaware.

Another example from the spring of 1974 was when Peppermint Patty, in protest, refuses to go to school, holding vigil on top of Snoopy's doghouse (which Patty still refers to as Chuck's guest cottage). Eventually Marcie's anger again gets the better of her and, while pulling Peppermint Patty down, destroys the doghouse. In so doing, Marcie also makes Peppermint Patty face the reality that Snoopy is a beagle, and not the "funny-looking kid with the big nose" as Peppermint Patty often refers to him.