Cosby was born in Los Angeles, the third of five children (and the only son) of Bill and Camille Cosby. On his 1969 television special, Bill Cosby had joked to his then-pregnant wife that the baby “had better be a boy, you hear, Camille?” The character of Theo Huxtable, portrayed by Malcolm Jamal Warner on NBC’s The Cosby Show, was based on Ennis. Bill Cosby also wrote situations and conversations that he had with Ennis into the series.  Cosby attended Eaglebrook School in Deerfield, Massachusetts and graduated from George School in Newtown, Pennsylvania. In 1988, he enrolled in Morehouse College, but after being diagnosed with dyslexia, he transferred for a time to Landmark College, which had a specific dyslexia program. He returned to Morehouse and graduated in 1992. In 1995, he earned a master’s degree in education from Columbia University.  Although he had performed on stage in high school, Cosby remained a private figure. Cosby aspired to become a special education teacher, having served an internship in special education at a school on Manhattan’s West Side. At the time of his death, he was pursuing his doctorate at Teachers College, Columbia University and living near his parents’ home on Manhattan’s East Side.

In January 1997, Cosby was visiting Los Angeles while on a break from school. On the evening of January 16, Cosby was driving on Interstate 405 on his way to visit his friend, Stephanie Crane, when his car developed a flat tire. He telephoned Crane, who drove out to assist him. While Cosby changed the tire, Crane sat in her own car shining the headlights on Cosby to illuminate the area. An armed man wearing a knit hat then approached Crane’s driver-side window and ordered her out of the car and threatened to kill her. Crane quickly drove off but returned to Cosby’s car minutes later to see the man running away. She then noticed that Cosby was lying next to his car with a fatal gunshot wound to the head. Cosby had been shot in the temple and was killed instantly. He was pronounced dead at the scene.  Ennis Cosby’s private funeral was held on January 19, 1997 at the Cosby family estate in Shelburne, Massachusetts. Afterwards, he was buried on the grounds of the estate.