After Linus van Pelt and Snoopy, Schroeder is probably Charlie Brown's closest friend; he once angrily denounced Violet for giving Charlie Brown a used valentine well after Valentine's Day had come and gone (only to be undercut when Charlie Brown eagerly accepted it), and he is one of the few baseball players who has any respect for Charlie Brown as a manager (although he is as capable of ire at Charlie Brown's poor performance as anyone else, such instances are few and far between).
Schroeder was introduced as a baby on May 30, 1951. Within a short time, however, he had aged to nearly the same age as the other characters. He initially had no notable characteristics, but Schulz eventually had the idea to incorporate his daughter Meredith's toy piano into the strip. He decided to give it to the strip's newest character, and thus the character as he is known to millions of fans was born.
Ludwig van Beethoven is Schroeder's favorite composer, as revealed in the February 27, 1955 strip. In it, Lucy takes his bust of Beethoven and smashes it, but Schroder simply takes another one from a closet full of Beethoven busts. Every year, Schroeder marks Beethoven's birthday on December 16, although one year he was in shock when he forgets it. When Charlie Brown's baseball team was required to have a sponsor to play games, Schroeder chose "Beethoven" as a sponsor. In the early strips, Schroeder also played music by other composers. Schulz once remarked that he had originally decided to depict Johannes Brahms as Schroeder's favorite composer, but decided that Beethoven sounded "funnier".
Another distinguishing character trait of Schroder is his constant refusal of Lucy's love. Lucy is infatuated with Schroeder, and frequently leans against his piano while he is playing, professing her love for him. However, since Beethoven was a lifelong bachelor, Schroeder feels that he must emulate every aspect of his idol's life - even if it insinuated that he reciprocates Lucy's feelings. In a story arc where she and the rest of her family have moved out of town, Schroeder becomes frustrated with his music and mutters disbelievingly that he misses her. Despite his constant animosity towards her, Schroeder would come to realize that Lucy has unwittingly become his muse and he cannot play without her.
Schroeder is a member of Charlie Brown's baseball team, often seen as a catcher (notably as far from outfielder, Lucy, as possible). In this capacity, he has often been shown to provide backhanded compliments on Charlie Brown's pitching. Also, he will run through a list of complicated signals, only to end up with something to the effect of, "Just throw it down the middle. He'll hit it out no matter what you throw, anyway." He is also described as a good hitter, 'one of the best on the team' Charlie Brown said in one strip. He has also shown a love for hockey in some of the Peanuts comic strips, as well as some television specials.
The shirt that Schroeder wears has thick black stripes.
Schroeder is one of Charlie Brown's closest friends. They have conferences on the pitcher's mound, in between pitches, mostly about Beethoven. He also often encourages Charlie Brown during a baseball game, whereas the rest of the team say, "Don't let us down by showing up!"
Charlie Brown is one of the few people Schroeder will allow to lounge against his piano, as he and Charlie Brown are good friends, and he knows that Charlie Brown respects his love of Beethoven. When they were younger, Charlie Brown would read Schroeder the story about Beethoven's life. Charlie Brown, in fact was the one that introduced Schroeder to the piano.
At various times Schroeder has been the first to defend Charlie Brown, for example, in one strip he berates Violet for giving Charlie Brown a used Valentine the day after Valentine's day just to avoid any guilt.
Schroeder does not appreciate Lucy's love for him. He says, he can not like Lucy, because Beethoven was a lifelong bachelor, and Schroeder feels he must emulate every aspect of his idol's life, even if it is insinuated that he reciprocates Lucy's feelings.