Perlman began working on the screenplay in 2009. Producer Kevin Feige first publicly mentioned Guardians of the Galaxy as a potential film in 2010 and Marvel Studios announced it was in active development at the July 2012 San Diego Comic-Con. Gunn was hired to write and direct the film that September. In February 2013, Pratt was hired to play Peter Quill / Star-Lord, and the supporting cast members were subsequently confirmed. Principal photography began in July 2013 at Shepperton Studios in England, with filming continuing in London before wrapping up in October 2013. In addition to an original score by Tyler Bates, the film’s soundtrack includes several popular songs from the 1960s and 1970s chosen by Gunn. Post-production was completed on July 7, 2014.

Guardians of the Galaxy premiered at the Dolby Theatre in Hollywood on July 21, 2014, and was theatrically released in the United States on August 1, as part of Phase Two of the MCU. The film became a critical and commercial success, grossing $772.8 million worldwide and becoming the highest-grossing superhero film of 2014, as well as the third-highest-grossing film of 2014. The film was praised for its screenplay, direction, acting, humor, soundtrack, visual effects, and action sequences. At the 87th Academy Awards, the film received nominations for Best Visual Effects and Best Makeup and Hairstyling, and also won the Hugo Award for Best Dramatic Presentation in 2015. The sequel, Guardians of the Galaxy Vol. 2, was released in 2017. The third film, Guardians of the Galaxy Vol. 3, will be released in 2023.