 The family was conceived by MacFarlane after developing two animated films , The Life of Larry and Larry & Steve . MacFarlane redesigned the films ' protagonist , Larry , and his dog , Steve , and renamed them Peter and Brian , respectively . MacFarlane pitched a seven @-@ minute pilot to Fox in 1998 , and the show was greenlit and began production . Shortly after the third season of Family Guy had aired in 2002 , Fox canceled the series , with one episode left unaired . Adult Swim burned off the episode in 2003 , finishing the series ' original run . However , favorable DVD sales and high ratings for syndicated reruns on Adult Swim convinced the network to renew the show in 2004 for a fourth season , which began airing on May 1 , 2005 . 
