Peter Costa, who played Huxtable neighbor and Rudy's playmate Peter suffered stage fright, and due to that would often forget his lines. This resulted in his character's communication via trademark facial expressions and always running out of the house at the sign of trouble.
The character of Sondra, the Huxtables' eldest daughter, was added almost as an afterthought. In the pilot, 'Phyllicia Rashad's' Clair Huxtable mentions the couple's four children (Sondra makes it five). They decided there should be another child that represented the results of a good upbringing, hence a daughter in college. When casting the role, it came down to two actresses: 26-year-old Sabrina Le Beauf and 21-year-old Whitney Houston. LeBeauf's theater experience won her the role.
Inspired by I Love Lucy (1951), Cosby intended for Clair to be a Dominican who would go into Spanish tirades when she got angry. Phylicia Rashad, who learned fluent Spanish from living in Mexico as a child, won the part by demonstrating her language skills, but this idea was dropped before the pilot was taped. Clair is shown speaking Spanish in a few episodes.
Nobody gave this sitcom much chance for success partly because it was on Thursday night against Magnum, P.I. (1980), a very popular CBS drama series at the time. The sitcom eventually became the number-one show on the air and routinely beat Magnum in the ratings. In one episode of the show, Cosby wore a Magnum baseball cap.
Phylicia Rashad was pregnant throughout much of the third season. As a result, her scenes were greatly reduced and what little she was used in, she had to hide her condition, such as sitting behind a desk.
After the 2008 election, Republican strategist 'Karl Rove' credited The Cosby Show (1984) with paving the way for America to elect an African American president, since, in Rove's words, "we've had an African-American first family for many years in different forms. When 'The Cosby Show' was on, that was America's family. It wasn't a black family. It was America's family."
In November 2008, The New York Times reported that during the mid-1990s, a UMass communications professor named Sut Jhally got Bill Cosby to donate $16,000 to him so that he could do research on why "The Cosby Show" had been popular with white viewers as well as black viewers. Dr. Jhally insists that Cosby's money did not bias the study, and in fact the book that Jhally wrote as a result of that research, "Enlightened Racism: The Cosby Show, Audiences, and the Myth of the American Dream", was critical of the show.
Malcolm Jamal-Warner failed his initial audition for the show. When reading a scene with Bill Cosby, Cosby felt that that Warner was speaking in a disrespectful nature. When Cosby asked Warner if he spoke to his own father that way, Warner replied "No", earning him a second chance to audition.
In one of the earlier episodes, Theo buys a shirt by designer Gordon Gartrelle. Throughout the series, the real-life Gordon Gartrelle worked in various jobs for the series and is listed as a producer of the show during the last few seasons.
The first episodes of the show's next-to-last season had an opening in front of a Mother Hale mural. However, when there was a disagreement over what compensation would be paid to the kids who painted the original mural, the show switched back to its previous season's Apollo Theater-themed opening with an added graphic for Erika Alexander, who became a regular on the show. Some episodes began with Bill Cosby and 'Raven (VII)' telling the viewers that it was not a repeat. The final season used a slightly modified version of the Mother Hale opening.
Cliff, Claire, and Cliff's father Russell were all graduates of the fictional Hillman College. Hillman would serve as the setting for the show's lone spin off A Different World (1987), which initially featured Denise as a student there.
When Rudy was to be a boy, Jaleel White was among those who auditioned for the part, and was a front runner for the role. Coincidentally, one of White's first TV appearances was in a Jell-O Pudding commercial with Bill Cosby.
One of the challenges in developing and launching the series was at that time, Sitcoms were widely viewed as a dying genre. The success of the series helped inspire the creation and launch of several new Sitcoms, and the show is generally credited with helping to revive the Sitcom genre.
During the second season, in the episode "The Juicer", the exterior of Dr. Cosby's office is shown in which the nameplate "Dr. Heathcliff Huxtable" is hanging. However, in the first episode of the last season, Clair calls him Heathclifford.
During the early 1980's, Bill Cosby regularly served as Johnny Carson's substitute as host of The Tonight Show. Reportedly, when NBC program executive Brandon Tartikoff was up late one night tending to his infant daughter, he happened to turn on an episode of the Tonight Show hosted by Cosby. Watching Cosby's monologue, which centered around observations of his family life, Tartikoff was struck by the inspiration to develop a family sitcom starring Cosby for NBC.
During the third season, Lisa Bonet appeared only sporadically as Denise was away at college. In season four, Bonet was spun off into her own series, A Different World, portraying Denise's life at the fictional Hillman College. Bonet's real life pregnancy resulted in her being forced to leave A Different World, which would continue a successful run without her. Subsequetly, Bonet returned to the Cosby Show for season five and remained on and off until being let go due to creative differences during season seven.
At one point during the series, on the back of Rudy and Vanessa's room door it was a poster of Whitney Houston. Whitney Houston was originally considered for the role of Sondra Huxtable but wanted to do her music
With the exception of Sabrina Le Beauf (eldest child, Sondra) and Keshia Knight Pulliam (youngest child, Rudy), all of the actors who play the Huxtable children are almost or accurately the same age as their real-life counterparts: Lisa Bonet is a year younger than Erinn Cosby, Malcolm-Jamal Warner is a year younger than Ennis Cosby, and Tempestt Bledsoe was born the same year as Ensa Cosby.