In the original novel Who Censored Roger Rabbit?, Eddie Valiant is a fictional modern day California private detective hired by comic book star Roger Rabbit to investigate the workings of Roger's corrupt employers, the DeGreasy Brothers. When Roger is found dead, and his final words having been censored out, Valiant is soon sent on the case of tracking Roger's murderers. This original incarnation of Eddie is a heavy smoker and has a beard.
The 1988 film gives insight into the character, as portrayed by Bob Hoskins. Pictures and newspaper clippings in his office reveal that he and his brother Theodore ("Teddy" for short) were sons of a circus clown; they joined the police force in 1925 and started their own private investigation service in 1938. The brothers quickly established a reputation for helping Toons in trouble, such as solving the kidnapping of Donald Duck's nephews and clearing Goofy of espionage charges. In 1942, while they were investigating a robbery in Toontown, an unknown assailant (later revealed as Judge Doom) dropped a piano on them. Eddie survived with a broken arm, but Teddy was killed. The incident soured him on the idea of working for Toons, his business suffered greatly, and he became an alcoholic. Eddie began living in the office he and Teddy had shared and left Teddy's desk as a memorial to him, refusing to dust it or let anyone sit in its chair.
In 1947, R.K. Maroon, head of the Maroon Cartoons studio, hires Valiant to photograph Jessica Rabbit, Roger's wife; she is literally "playing pattycake" with Marvin Acme, owner of Toontown and founder of the Acme Corporation. When Acme is murdered and Roger becomes the prime suspect, Valiant teams up with Roger to find the culprit. Maroon is subsequently killed, and Valiant discovers that Doom is responsible for not only these two deaths, but Teddy's as well. He defeats Doom at Acme's warehouse, finds Acme's lost will that bequeaths Toontown to the Toons, and abandons his prejudice against them.
In the graphic novel of the film published in 1989 by Marvel Comics, Valiant is the narrator of the story, telling the film through his eyes and in the style of a detective story. According to Roger Rabbit: The Resurrection of Doom, Valiant tends to eat jellybeans quite a bit as he gave up drinking. In the novel Who P-P-P-Plugged Roger Rabbit?, Valiant has once again vowed to no longer take any Toon cases, but is forced to do so when Baby Herman is found dead.