Throughout the Season
Seth lives in the Foley residence with Justin and his mother. When Jessica Davis came to see Justin, Seth told her that she needs to tell Justin that if he doesn't call that day he doesn't have to bother coming home.
At the Foley residence, Seth sat with Amber watching TV when Justin walked in. Justin noticed that Seth had his feet on top of his school books, so he told Seth to take his feet off his books. Seth rubbed his feet on the books until Justin pushed them off the table. They argued, and Justin left because his Mom took Seth's side.When Justin came home after a sheriff had come to the house to serve Justin with a subpoena, Seth confronted him about it and told him about how he doesn't want the sheriff's department at his door because of his drug dealing. Justin told him it's not his door, but before he could finish his sentence, Seth proceeded to strangle Justin and told him how he's no good to his Mom, his girlfriend, or anyone. He then told Justin to go live with Bryce Walker, and Justin stole $1000 and a gun from Seth.
In the second season, Kevin Porter stopped by Seth and Amber's house to ask about Justin. Seth told him to either pay him back the money that Justin stole or to get off of his property. Seth pushed Mr. Porter, which caused a fight between both men, and they got arrested.After Justin stole more money and his Mom left, Seth was seen angrily staring down an unaware Justin down from his car.
In the third season, Seth went after Justin for the money he stole from him. He made Justin deal drugs for him to pay back his money. After finding out Justin had been using part of the drugs he was supposed to sell himself, Seth threatened him with a gun, saying he wants his money back within a day, or he would go after Justin's new family. Bryce gave Seth the money Justin had to pay him, plus a few thousand extra for him to leave Justin alone.
Seth continued bothering Justin, watching him while playing football and standing outside his house. After Bryce's body was found, Seth texted Justin "You're next".
Justin and Seth met up again, because Justin had an offer; Seth would get rid of the dealer Justin bought from the night of Bryce's disappearance so he could be Clay's alibi, and Justin would deal drugs for as long as he wanted.At the end of the season, it's revealed Seth was arrested for parole violations and won't be out anytime soon.
Seth is a very aggressive and abusive drug dealer. This is especially shown when he fights with Kevin Porter over being on his property and when he strangles Justin over receiving a subpoena. It is implied that he has abused both Justin and Amber several times. It was also mentioned that Seth gets taken by the police about once a week. Despite doing horrendous things himself without showing any remorse, Seth pointed out to Bryce that his rape of Jessica was messed up.
Seth is a caucasian of average-height with light brown hair and several tattoos over his body. He's of average height and has a beard.
- He may be a neo-Nazi or at least racist, as he has tattoos of an iron cross on his chest and SS bolts on the back of his neck.
- See also: Category:Images of Seth Massey
- Son, Diana (writer) & Shaver, Helen (director) (March 31, 2017). "Tape 2, Side A". 13 Reasons Why. Season 1. Episode 3. Netflix.
- Son, Diana (writer) & Yu, Jessica (director) (March 31, 2017). "Tape 6, Side A". 13 Reasons Why. Season 1. Episode 11. Netflix.
- Benjamin, Elizabeth (writer) & Yu, Jessica (director) (March 31, 2017). "Tape 6, Side B". 13 Reasons Why. Season 1. Episode 12. Netflix.
- Sheff, Nic (writer) & Hittman, Eliza (director) (May 18, 2018). "The Chalk Machine". 13 Reasons Why. Season 2. Episode 5.
- Tyler, Hayley (writer) & Yu, Jessica (director). (May 18, 2018). "Bye". 13 Reasons Why. Season 2. Episode 13.
- Malone, M.K. (writer) & Guerrero, Aurora (director). (August 23, 2019). "Always Waiting for the Next Bad News". 13 Reasons Why. Season 3. Episode 9.
- Shang, Helen (writer) & Dowling, Kevin (director). (August 23, 2019). "There Are a Few Things I Haven't Told You". 13 Reasons Why. Season 3. Episode 11.
- Yorkey, Brian (writer) & Kretchmer, John T. (director). (August 23, 2019). "Let the Dead Bury the Dead". 13 Reasons Why. Season 3. Episode 13.