The original writer said he had the Franklin idea for years and his handlers fought him on it. Then he said fuck it I'm leaving and they let him add the character with a bunch of BS stipulation that he worked around for years.
Franklin made his first appearance in the newspaper strip on July 31, 1968, prompted by a request from a school teacher for Schulz to integrate his comic strip world in the wake of the assassination of The Rev. Martin Luther King Jr.
en.m.wikipedia.org
A Los Angeles schoolteacher named Harriet Glickman wrote to Schulz on April 15, 1968 (eleven days after the
assassination of Martin Luther King Jr.), urging him to introduce a black character into
Peanuts.
[4] On April 26, Schulz wrote back, saying that he had thought about this, but was afraid of "patronizing our Negro friends."
[5] This began a correspondence between Schulz and Glickman that led to Schulz's creation of Franklin.
[6][7]
In an interview in 1997, Schulz discussed receiving a letter from a Southern editor "who said something about, 'I don't mind you having a black character, but please don't show them in school together.' Because I had shown Franklin sitting in front of Peppermint Patty... I didn't even answer him."
[8] Franklin's skin color was mentioned in
The Charlie Brown Dictionary, a
picture dictionary using the Peanuts characters; he was referred to in the definition of "black" in showing a picture of him talking on the telephone, where the color of the telephone is black. The description also says that "black may also refer to Franklin's skin tone, which is also known as a
Negro person."
[9]