Who originally voiced Scooby-Doo in the 1969 animated series?

Don Messick originally voiced Scooby-Doo in the 1969 animated series.

Messick was an American voice actor whose career included numerous Hanna-Barbera productions. He supplied Scooby-Doo’s distinctive speech pattern, including the character’s habit of placing an extra “r” sound in words, such as “Ruh-roh!” Messick also voiced other animated characters, including Astro from The Jetsons.

Scooby-Doo is unusual among major animated characters because the same performer voiced both the dog and another central character in the original cast: Messick played Scooby, while Casey Kasem played Shaggy Rogers. Frank Welker, who voiced Fred Jones in the original series, later became the long-running voice of Scooby-Doo beginning in the 2000s. This later casting history sometimes causes confusion, but Messick is the original Scooby voice.