Sam was introduced in the show as Annalise's husband, introducing himself to the classmates as a professor at Middletown. He told them that they should not doubt his knowledge just because he doesn't teach law.
He was killed by Wes as revenge for having Lila murdered and almost killing Rebecca.
The keating five (except Asher) had to burn him in the campus forest to burn the DNA so the police wouldn't find the body. They then put his body parts in the trash near the campus and a couple of days later it was found in the local dump. The police had his DNA sample that they took to prove that he was guilty for the murder of Lila Stangard.
A flashback scene shows that Sam had ordered the killing of Lila Stangard because she was pregnant by him (Frank carried out the murder).
This is a gallery of photographic stills released to promote the character.