The memorable "Aaaugh!" scream from Peter Robbins as Charlie Brown originated from this film. (Oddly enough, it was also heard from Linus in one scene.) Robbins' scream would become a stock sound effect in almost all subsequent Peanuts specials & movies up to the late 1990s, and is used as a scream, not only for Charlie Brown, but any other available character (excluding Snoopy and Woodstock, who had their own variants).
Peppermint Patty makes a brief appearance in one shot (behind Frieda), among a group of children cheering for Charlie Brown upon successfully spelling "perceive" in the class spelling bee. She would finally become a major character in the next film, Snoopy Come Home (1972).
The main story line of this movie, involving Charlie Brown's participation in a spelling bee, was taken from a sequence that originally appeared in the comic strip. In that story, however, Charlie Brown lost in the first round of the competition, misspelling the word "maze" M-A-Y-S. He later loses his temper at the teacher and is sent to the principal's office; as he waits in the hall, he reflects that the reason he misspelled the word was that when he heard the word "maze," the first thing he thought of was the surname of famed baseball player Willie Mays. This last half of the story had been used in You're in Love, Charlie Brown (1967), when Charlie Brown inadvertently yelled at the teacher for "missing the stupid bus" (after he overslept).
"A Boy Named Charlie Brown" was the *very first* animated film produced by CBS Films, which was known as Cinema Center Films at that time. Cinema Center would be active until late 1972, after which CBS closed their theatrical film division and didn't reactivate it until 1982, when the company would be called CBS Theatrical Films. (Ironically, the second "Peanuts" film three years later, Snoopy Come Home (1972), would be the *last* Cinema Center production). Naturally, CBS *still* owns "A Boy Named Charlie Brown," and their sister company, Paramount Home Entertainment, has released the film on DVD (along with "Snoopy Come Home").
The version of "Linus and Lucy" heard when Linus is reunited with his blanket is the opening track of It's the Great Pumpkin, Charlie Brown (1966). A different arrangement of "Linus and Lucy" was done for this scene, but was never used in the finished film. It was, however, heard in the Columbia Records story LP released in conjunction with this film.
The opening scene with Charlie Brown, Linus, and Lucy looking at the clouds in the sky (translated from one of Charles M. Schulz's "Peanuts" strips, became the subject for one of the songs, "Clouds," in the 1975 musical, "Snoopy, the Musical," one of two musicals based on Schulz's famous characters. (The other being "You're a Good Man, Charlie Brown," from 1967.)
The 1964 LP and CD "A Boy Named Charlie Brown" by the Vince Guaraldi Trio (Fantasy FCD-8430-2), long since available by Fantasy Records, is not the soundtrack for this film, but for the earlier unaired TV documentary of the same name, A Boy Named Charlie Brown (1963). A storybook record for this film, featuring the music & song tracks (by Guaraldi, John Scott Trotter and Rod McKuen), and the dialogue (with narration by Peter Robbins as Charlie Brown and Glenn Gilger as Linus Van Pelt), was released by Columbia Records to coincide with the release of this film, but has since been out of print. Another LP album by Rod McKuen (SR-5010) was released on his Stanyan Records label in 1970, featuring new arrangements of the songs he did for the film (along with an instrumental track, called "Something For Snoopy," originally intended for the film); it was finally released on CD and digital in 2015. However, in 2017, Kritzerland Records has released the long-awaited complete score for this film (KR-20031-8) with bonus unused/alternate tracks) on CD, albeit limited edition (1,000 copies).