 Seth MacFarlane voices three of the show 's main characters : Peter Griffin , Brian Griffin , and Stewie Griffin . Since MacFarlane had a strong vision for these characters , he chose to voice them himself , believing it would be easier than for someone else to attempt it . MacFarlane drew inspiration for the voice of Peter from a security guard he overheard talking while attending the Rhode Island School of Design . Stewie 's voice was based on the voice of English actor Rex Harrison , especially his performance in the 1964 musical drama film My Fair Lady . MacFarlane uses his regular speaking voice when playing Brian . MacFarlane also provides the voices for various other recurring and one @-@ time @-@ only characters , most prominently those of the Griffins ' neighbor Glenn Quagmire , news anchor Tom Tucker , and Lois ' father , Carter Pewterschmidt . 
