Sam is the owner of Merlotte's, where Sookie works. During the first season, Sam is characterized by his adoration and loyalty towards Sookie Stackhouse. When Bill Compton becomes involved with Sookie, he openly disapproves of their relationship and (despite initially showing support for equal vampire rights and selling Tru Blood at his bar) feels as though vampires and humans should be separate whether they're equals or not. Despite his distrust of Bill, he saves Bill's life at the end of the first season by burying his charred body to hide it from the sunlight. Sam has a brief relationship with Tara Thornton during the first season, but by the time Maryann Forester returns to Bon Temps the two have gone their separate ways romantically. Sam is also a shapeshifter, often watching over Sookie in the form of a dog, and the first supernatural introduced to the series that isn't a vampire. He keeps his nature as a shapeshifter hidden from Bon Temps, and (though vampires appear to be able to recognize what he is on sight) Sookie is the only human resident to know his secret during the first season. In the first and second season, details about Sam's life before the events of the series are revealed in flashback sequences. For instance, it's revealed that he is abandoned by his adoptive family as a child after they witness him turn into a beagle. Without guardians to care for him, he's next shown invading Maryann's home when he's seventeen. After being discovered and having a brief affair with her, he steals some of her belongings and $100,000 before running away. Sam later uses the money he steals to finance a business venture that would become Merlotte's bar.
During season two, he becomes romantically involved with Daphne, a new waitress at Merlotte's who is also a shapeshifter. Daphne is ultimately revealed to be involved with Maryann, and was seducing him so that he could be sacrificed to the god Dionysus. After Daphne's betrayal, Sam later discovers Daphne's body in the freezer at Merlotte's (killed by "Eggs" Talley while under Maryann's control). The Bon Temps police department is sent an anonymous tip to investigate the bar, and Sam is arrested as the prime suspect in Daphne's murder. Sam escapes police custody by assuming the shape of a fly, and spends the remainder of the season evading Maryann and the residents of Bon Temps under her possession. Sam discovers and cares for Arlene Fowler's abandoned children, and goes to Fangtasia to ask for help at their behest. In the concluding episode of the season, Bill approaches Sam to assist him in freeing the people of Bon Temps from Maryann with a plan he's devised. After being traded by Bill to Maryann for Sookie (who she's captured as her "maid of honor" in the ritual she's planned), Sam is stabbed through the heart. Dying, Sam tells Sookie to destroy the offering that Maryann has assembled for her god using his thoughts. Complying, Maryann flies into a rage when Sookie has destroyed the effigy she's assembled, and chases Sookie away from the Stackhouse home. Bill uses his blood to heal Sam, who then assumes the form of a large white bull. Intervening before Maryann can attack Sookie, Sam tricks the maenad into thinking he is her "horned god." As Maryann can only die when she's believed her life has been taken by the god that comes, Sam is able to remove her heart on his horn once he has her fooled. Reassuming his human shape, he crushes her black heart and kills her.
In the concluding scenes of the second season, Sam has a renewed interest in searching for his birth parents. Seeking out the aid of the adoptive parents that abandoned him, his former father provides him with the information he seeks.