His biggest success came in 1997, when he created "The Fairly OddParents". (The idea came to him during the drive from Hanna-Barbera to Nickelodeon to pitch an idea to Fred Seibert.) It was originally a series of made for TV shorts on the anthology show, "Oh Yeah!Cartoons". In 2001, Nickelodeon picked it up as a full series. "The Fairly OddParents" became a huge hit, second only in the ratings to "SpongeBob SquarePants". Due to the success of "OddParents", Hartman was asked to create another cartoon for Nickelodeon, (Hartman says the President of Nickelodeon asked him if he had an idea, and before he could say the title he was given a contract.) "Danny Phantom", in 2004. "The Fairly OddParents" ceased production in 2006, but it was announced on Hartman's website on February 2, 2007 that 20 more episodes will be produced. On July 11, 2007, The first new episode of Danny Phantom was aired on the Nicktoons Network. Danny Phantom ended production on August 24, 2007. The 7th Season of The Fairly OddParents aired on February 18, 2008, starting with the 1-hour special Fairly Odd Baby.