Arguably last year's biggest breakout series was "Stranger Things" from the Duffer Brothers, which rekindled the love for the sci-fi genre among TV viewers.

The show launched Millie Bobby Brown's television career and showcased David Harbour as a viable leading man or main hero. So much so that the 42-year old actor is now the face of the upcoming "Hellboy" reboot.

Harbour is no stranger to film and television. However, he appeared in "Pan Am," "The Newsroom," "Rake," "Manhattan," and "State of Affairs" for TV. He also appeared in several stage productions and was in the films "Brokeback Mountain," "Revolutionary Road," "Quantum of Solace," "The Equalizer," "Black Mass," and "Suicide Squad," among others.

The actor has recently finished filming "Stranger Things" Season 2 and is gearing up to play the titular character in the upcoming "Hellboy" reboot. But his journey isn't without challenges. Harbour recently opened up about how the business has at times affected his desire to continue his acting career.

David Harbour felt 'cynical' at one point in his career

The 42-year old star of "Stranger Things" season 2 recently opened up about his acting career, telling Gold Derby that at one point, he became "a little bit cynical about my place in film and TV."

This is from someone who earned a Tony nomination for his work in "Who’s Afraid of Virginia Woolf?" which he appeared on in 2005.

But coming to "Stranger Things" was a different experience for him, as he said the role and the experience "reinvigorated my belief in being able to tell a story that I really believed in."

Actor says 'Stranger Things' showcases 'flawed' people

"Stranger Things" Season 2 is set to debut on Netflix this October, and in it, David Harbour's Chief Jim Hopper is set to deal with the repercussions of being the hero who saved Will Byers in season 1.

The sophomore season will also shed light on Hopper's new relationship with Hawkins Laboratory as they strive to keep the events of season 1 a secret.

One of the best things about the show is how it features characters that sometimes make questionable choices, and Harbour stands by these characters and the way they were written.

He explained to Gold Derby, "We embrace real people and in a sci-fi genre...they have flaws, and they have problems, and I want to see more of that in my sci-fi, in my comic books, in characters that I admire."

"Stranger Things" season 2 will stream on Netflix on October 31.