1921 was a year in the 20th century.

Doc Brown had dollar bills from 1921 in his briefcase.[1]


Behind the scenes[]

Doc Brown was born in the 1920s. The novelization states that he was 65 years old in 1985, placing his birthdate in 1920, while the animated series placed his birthdate at 1922.

In commentary to Part III, Bob Gale said that he and Robert Zemeckis "toyed with the idea" of having a film sequel in which Doc and Marty go back to the "roaring '20s", where they would meet a bootlegging ancestor of Biff Tannen, Doc's mother, and other characters [2]. Ultimately, the choice was made instead to conclude the film as a Western in 1885.

The first issue of the Back to the Future comic series featured an adventure where Doc and Marty went back to the 1920s, going to Chicago in 1927.



  1. Back to the Future Part II novelization p. 163
  2. Commentary Part III, at 15:30