Scooby-Doo
The first episode of "Scooby-Doo, Where Are You!" "What a Night for a Knight" debuted on the CBS network Saturday, September 13, 1969. The original voice cast featured veteran voice actor Don Messick as Scooby-Doo, radio DJ Casey Kasem (later host of radio's syndicated "American Top 40") as Shaggy, actor Frank Welker (later a veteran voice actor in his own right) as Fred, actress Nicole Jaffe as Velma, and musician Indira Stefanianna Christopherson as Daphne. Scooby's speech patterns closely resembled an earlier cartoon dog, Astro from "The Jetsons" (1962–63), also voiced by Messick. Seventeen episodes of "Scooby-Doo Where are You!" were produced in 1969–70. The series theme song was written by David Mook and Ben Raleigh, and performed by Larry Marks.
Scott Innes
Innes became the voice of Scooby-Doo between 1998 and 2002 after Don Messick's death in 1997. From 1999 to 2002, he was also the voice of Scooby's best friend and owner Norville "Shaggy" Rogers. He was replaced by Frank Welker (as Scooby) and by Casey Kasem (as Shaggy) in 2002, although Innes still provided the voices in video game projects and some commercials until 2009. He also voiced Scooby's nephew Scrappy-Doo in the live action movie "Scooby-Doo" (2002).