Biff Tannen Sr.

Biff Tannen Sr. serves as the primary antagonist throughout the Back to the Future franchise, acting as the persistent bullying force that shadows the McFly family across multiple decades. In the original 1985 he is George McFly's supervisor and bullies him; after Marty changes history he is a servile auto detailer. However, his character takes a dramatic turn when he steals the DeLorean time machine in 2015. Using an almanac containing sports results from 1950 to 2000, he alters history to become one of the country's wealthiest and most corrupt men by 1985. This version of Biff transforms Hill Valley into a chaotic dystopia, secretly killing George McFly in 1973 and forcing Lorraine to marry him. His actions drive the central conflict of Part II, requiring Marty and Doc to travel back to 1955 to retrieve the almanac and restore the timeline.

Quick Facts

Affiliation: Tannen Family

Lore & Background

The alternate timeline begins in 2015, when the elderly Biff overhears Marty and Doc's conversation and retrieves the discarded almanac. After overhearing the discussion about the sports almanac (covering results from 1950 to 2000), an elderly Biff steals the DeLorean and travels back to November 12, 1955. He gives this book to his younger self, setting in motion a chain of events that creates an alternate 1985. In this distorted reality, Biff accumulates a fortune through gambling and corruption, turning Hill Valley into a lawless zone dominated by his casino.

He secretly murdered George McFly in 1973 and forced Lorraine into marriage with him. Meanwhile, the younger Marty was sent to boarding school in Switzerland, and Doc Brown was committed to a mental hospital. This timeline exists solely because of Biff's intervention, proving that his greed could reshape history until Marty and Doc intervened.

Reader's Guide

Biff Tannen Sr. represents the consequences of unchecked power and the dangers of altering history for personal gain. His role evolves from a high school bully in 1955 and George's abusive supervisor in 1985 to the corrupt ruler of Hill Valley in the alternate timeline. He has no special abilities; his dominance relies on physical intimidation, fear, and later, wealth derived from future knowledge. Key moments include stealing the DeLorean in 2015, giving the almanac to his younger self in 1955, and ruling as a corrupt billionaire. His defeat comes not through violence but through the restoration of the correct timeline when George McFly stands up to him in 1955 and Marty destroys the source of his power.