Dewolfe was born in Johannesburg, South Africa on August 02, 1989. He was adopted shortly before his first birthday by his parents who were on a humanitarian trip in the area. Shortly after returning to the United States, his parents divorced. His father lived in a partnership with another man until 2015 when they were legally wed. Rumors surround the validity of the marriage resulting in adoption but no one has ever commented publicly on the matter.

Dewolfe was homeschooled as he accompanied his father and his partner on various trips throughout Europe and Asia, before eventually returning to stay with a family friend in New York at the age of 13. It was then that Dewolfe took an interest in acting, doing various theater work and commercials, before landing a role in the 2005 film Speak.

While attending The Neighborhood Playhouse Junior School, Dewolfe filed for emancipation from his parents, citing career reasons. It was then that he was signed to a talent agency and able to pursue acting full time. In 2005, Dewolfe landed the role of Dave Petrakis in Speak, before following that up with appearances in Alpha Dog, Lords of Dogtown, and Bobby in subsequent years.

Dewolfe took time off from films in 2006 while attending the William Esper Studio's two year program, citing "if he were to make it big it wouldn't be by accident."

Dewolfe was next seen on screen in Tom Ford's A Single Man and they play Slipping as Eli, a role which he followed to the Los Angeles staging in 2013.

In 2011, he became part of the X-Men franchise as his role of Hank McCoy / Beast in the younger reboot and recieved acclaim for his role as Albert in War Horse on Broadway which saw multiple Tony Award wins during his run including Best Play.

Subsequent years saw Dewolfe in more dramatic roles, working with Lee Daniel's in both The Paperboy and The Butler and David Cronenberg's Map To The Stars. He was also part of the short film Whiplash, but was replaced by James Fornarola when the larger budget production was picked up. Similarly, Dewolfe workshopped the off broadway production of This Is Our Youth as Warren Straub but left before the show transferred onto Broadway.

2015 saw Dewolfe in one of the best heralded productions of the year, Mad Max: Fury Road, while also playing lead in one of the worst box office releases in history, We Are Your Friends. He is currently filming Billionaire Boys Club in the role of Joe Hunt and has a cameo in James Franco's film The Disaster Artist as Dan Janjigian.

Although Dewolfe can be frequently seen on social media, details of his family life have been kept to a minimum. He has said that his parents were not initially happy with his choice to pursue acting. Dewolfe has stated that his parent's passion of humanitarianism is important to him and when possible does join them in whatever country that they happen to be working in at the time.

Dewolfe has garnered a reputation among press as the "accessible James Fornarola", a comparison only grown stronger with the film Whiplash. He has never commented except to say that it means 'both of us are doing good work'.

After the dismal performance of We Are Your Friends at the box office, Dewolfe defended the project, stating "I always look to the director first before taking a role and I really believe Max had something to say. It's just a shame it wasn't heard".