Stan Smith is the main character from American Dad!.
He makes a brief appearance in "Excellence in Broadcasting". He is seen watching Family Guy, congratulating Brian for accepting conservative Republicanism.
Francine, Stan and the rest of the family appear as as part of a cold-opening for "Bigfat", with the scenes that were originally intended for "April in Quahog". When the Griffins greet their new neighbors, the Smiths, who moved into Cleveland's old house, Peter makes the same mistake Stewie did during his simulation in "Lois Kills Stewie" of mistaking Stan Smith for Joe. After Roger, Stan tries to keep Peter quiet but is forced to have to kill him as he starts to tell Quagmire about the alien. The entire opening turns out to be a dream by Hank Hill.
Stan is voiced by Seth MacFarlane.