Benjamin Géza Affleck-Boldt was born on August 15, 1972, to a middle-class family in Berkeley, California. At age three, his family moved to Cambridge, Massachusetts, where he grew up with his younger brother Casey. His father, Timothy Byers, was an aspiring playwright who made a living from multiple professions. His mother was an elementary school teacher, and her connections to the art scenes in Boston allowed Affleck to attend theater performances and audition for different roles. At only age seven, he appeared in his first film and continued to get several roles as a child actor.

Affleck attended Cambridge Rindge and Latin High School, where he played in many theater productions. After graduating high school in 1990, Affleck got accepted to the University of Virginia but instead enrolled at the University of Vermont to study Spanish. According to Affleck, his move to Vermont was to get closer to his high school girlfriend, who was in another school nearby. The love was unrequited, and he soon dropped out after suffering a leg fracture during a basketball game. At 18, Affleck moved to Los Angeles and enrolled in Occidental College, where he studied Middle Eastern affairs for about 18 months. During his time there, he directed several student films.

Soon, he decided to leave college completely to focus on his acting career. In 1992, he landed a role in his first major film, which also featured his childhood friend, Matt Damon. The same year, Affleck and Damon worked together on the screenplay for Good Will Hunting. After several challenges to get the film produced, Miramax bought rights to the film, released it in 1997. The film, which won the Academy and Golden Globe Awards for best original screenplay, turned the two struggling actors into overnight sensations.

After the film, Affleck got major roles in several films, including Armageddon, Pearl Harbor, and The Sum of All Fears. His career rose steadily, and today he is more recently known for his roles in Argo, Gone Girl, and as Batman in the growing line of DC comic movies. He has been featured in over 50 films and received accolades throughout his years as an actor, director, and writer.

In 2005, Affleck married Jennifer Garner. The couple has three children together. They separated in 2015 and filed for divorce in 2017. The Oscar-winning director received an honorary Doctor of Fine Arts degree from Brown University in 2013.