Originally starting out as a model for brands like Abercrombie & Fitch, he eventually transitioned into acting. While most of his roles to date have been television-based, he's since started branching out into film roles; 2015's San Andreas is his first credited film appearance.
- Transformers (2007) as Cafe Kid (uncredited)
- CSI: Miami (2007) as Brandon Fox
- Privileged (2008) as Alexander
- Pushing Daisies (2008) as Ares Kostopoulos
- Melrose Place (2009) as Jessie Roberts
- The Gates (2010) as Brett Crezski
- Teen Wolf (2011 — 2012, 2017) as Jackson Whittemore
- The Nine Lives of Chloe King (2011) as Kai
- Arrow (2013 — 2016, 2018 — 2020) as Roy Harper / Arsenal
- Flash vs. Arrow (2014)
- San Andreas (2015) as Joby O'Leary
- Avengers Academy (2016) as Thor (voice)
- The Grinder (2016) as Luke
- Scream Queens (2016) as Tyler
- Rough Night (2017) as Scotty
- American Horror Story: Cult (2017) as Det. Samuels
He provides examples of:
- The Cameo:
- Haynes briefly appears in the music video for Andy Grammar's song "Honey, I'm Good". In a video featuring different couples celebrating how long they've been together, Haynes is seen waving a sign saying "third wheel" next to one of the couples.
- In "Industry Baby" by Lil Nas X, he plays a prison guard who secretly has a crush on the rapper.
- Creator Breakdown: Haynes has a long struggle with anxiety and depression due to his past, turning to alcohol and drugs to cope. He departed from Arrow in 2015 for this reason. After he had sufficiently recovered, however, he could not be happier to return to the show (and he eventually did).
- Dark and Troubled Past: As a gay man who grew up in rural Kansas and the South, Haynes led an unhappy childhood life. When he came out to his parents at the age of 14, his mother ordered him to leave the house (although he later returned). His father committed suicide several years later and he was told the reason was because of the shock he experienced upon finding out that his son is gay. As a result, he became closeted for years, only publicly coming out in 2016.
- Mr. Fanservice: His more prominent roles have utilized him as this, complete with requisite shirtless scenes. Rough Night is probably the apex example of this for him, since he plays an actual stripper in that film.
- Pretty Boy: He tends to ebb and flow between being this and Mr. Fanservice, usually simultaneously.