<P> John Ritter voiced Clifford in all episodes . This was originally done by Brent Titcomb in the series that debuted in 1988 and ran into the early 1990s . Generally speaking, his schedule dictated the production of Clifford the Big Red Dog . By the time the last of the 68 half - hour cartoons and the movie were completed, Ritter was back on ABC's prime - time schedule, starring in 8 Simple Rules . Ritter's death on September 11, 2003 came less than a week before PBS debuted Clifford's Puppy Days, a function of keeping Clifford's legacy going . </P> <P> While no new Clifford episodes have been released since Ritter's death in 2003, voice actors for the main characters have reprised some of their roles for the Ready to Learn PBS Kids PSAs . The film Clifford's Really Big Movie serves as the series finale due to Ritter's death, as no new episodes were made to continue from where it left off . However, Clifford's Puppy Days still continued to air until its cancellation in 2006 . </P> <Ul> <Li> Clifford the Big Red Dog (voiced by John Ritter; Tom Eastwood in the British version): A giant red Labrador Retriever / Vizsla cross . The depiction of Clifford's size is inconsistent; he is often shown as being about 25 feet tall (7.6 m) from paws to head, but can appear far larger . The character is based on the imaginary friend of creator Norman Bridwell's wife . Clifford is devoted to his owner Emily Elizabeth . He is friendly, shy, lovable, loyal, gentle and helpful but sometimes gets into trouble because of his size, or is tempted into trouble by his friends and those he meets . Despite being the protagonist, he seldom has episodes focusing on him, usually serving as the voice - of - reason for his friend's adventures . </Li> <Li> Cleo (voiced by Cree Summer; Regine Candler in the British version): An energetic, selfish, trouble - making purple poodle with a tendency to not tell the truth . Her catchphrase is "Have I ever steered you wrong?" which she inadvertently does immediately after . She is one of Clifford's best friends . Her owner is Mrs. Diller . </Li> <Li> T - Bone (voiced by Kel Mitchell; Benjamin Small in the British version): A male yellow and orange bulldog with a large appetite . He is often cowardly, clumsy, and cautious, but does have his moments of bravery . He is one of Clifford's best friends . T - Bone is in love with Mimi, another dog who visits from time to time . His owner is Sheriff Lewis . <Ul> <Li> T - Bone had a best friend named Hamburger (voiced by Kel Mitchell's longtime comedy partner Kenan Thompson) who moved away before Clifford arrived . </Li> </Ul> </Li> <Li> Mac (voiced by Cameron Clarke): A male blue greyhound with an inflated sense of self - importance, who shifts between aloofness and wanting to be part of Clifford, Cleo, and T - Bone's circle of friends . Mac competes in dog shows . He can be vain, bossy and selfish . However, he appears to be devoted to his owner Jetta . It is revealed in a few episodes that his name is short for Machiavelli . </Li> </Ul> <Li> Clifford the Big Red Dog (voiced by John Ritter; Tom Eastwood in the British version): A giant red Labrador Retriever / Vizsla cross . The depiction of Clifford's size is inconsistent; he is often shown as being about 25 feet tall (7.6 m) from paws to head, but can appear far larger . The character is based on the imaginary friend of creator Norman Bridwell's wife . Clifford is devoted to his owner Emily Elizabeth . He is friendly, shy, lovable, loyal, gentle and helpful but sometimes gets into trouble because of his size, or is tempted into trouble by his friends and those he meets . Despite being the protagonist, he seldom has episodes focusing on him, usually serving as the voice - of - reason for his friend's adventures . </Li>

Who is the voice for clifford the big red dog