<P> American Dad! centers on the absurd circumstances, adventures and domestic life of its title character Stan Smith, his immediate family, and their three housemates . Adding to all the ridiculousness and absurdity are the various personality traits of all the show's eccentric main characters, listed as follows: </P> <Ul> <Li> Seth MacFarlane voices Stan Smith (father / husband) and Roger (alien) </Li> <Li> Wendy Schaal voices Francine Smith (wife / mother) </Li> <Li> Scott Grimes voices Steve Smith (Stan and Francine's son) </Li> <Li> Rachael MacFarlane voices Hayley Smith (Stan and Francine's daughter) </Li> <Li> Dee Bradley Baker voices Klaus Heissler (the Smiths' man - in - a-fish - body pet) </Li> <Li> Jeff Fischer voices Jeff Fischer (Hayley's boyfriend then husband) </Li> <Li> Patrick Stewart voices Deputy Director Avery Bullock (Stan's Boss) </Li> </Ul> <Li> Seth MacFarlane voices Stan Smith (father / husband) and Roger (alien) </Li> <Li> Wendy Schaal voices Francine Smith (wife / mother) </Li>

Who does seth macfarlane play on american dad