When viewing the rough cut of the show, both Bill Melendez and Lee Mendelson were convinced that they had a flop on their hands. After it premiered, they were happily surprised and shocked at the high ratings and excellent reviews that the show received. Today, the show remains the second longest-running Christmas special on US network television (the 1964 Rudolph the Red-Nosed Reindeer (1964) premiered one year earlier and is still broadcast every year on US network television).
Cathy Steinberg, who did the voice of Sally Brown, had not yet learned to read at the time of production so she had to be fed her lines, often a word or syllable at a time, which explains the rather choppy delivery of the line "All I want is what I have coming to me. All I want is my fair share."
Broke many of the rules prevalent for animated holiday specials during the 1960s: it didn't make use of a laugh track, real children were used for the character voices instead of adult actors imitating children's voices, and Biblical references were used to illustrate the true meaning of Christmas.
When they first saw the show, CBS executives were horrified at the idea of an animated Christmas special with such a blatant message. They also strongly objected to the fact that the show had no canned laughter. In addition, they greeted Vince Guaraldi's jazz score as an intrusion in the special that audiences would never accept. However, when CBS learned to their astonishment of the special's spectacular ratings earned on its initial broadcast and the glowing reviews for it, the network promptly contracted the producers for more specials.
When "A Charlie Brown Christmas" won an Emmy for Outstanding Children's Program in 1966, only Lee Mendelson and Bill Melendez were called up to accept the award, but they made sure that Charles Schulz was with them to give the acceptance speech. Schulz's speech simply went, "Charlie Brown's not used to winning, so we thank you."