He appears to possess great admiration for scientists from previous eras, naming successive pet dogs Copernicus and Einstein, and having portraits of Isaac Newton, Benjamin Franklin, Thomas Edison and Albert Einstein in his laboratory. His favorite author is Jules Verne and his family name was originally "von Braun" prior to World War I.

Emmett's family moved to Hill Valley from Germany in 1908. Although initially wealthy because of his inheritance, he spent his entire family fortune on his time travel project. When the Brown mansion was destroyed by fire in 1962 and the property sold to developers, Doc subsequently resided in the mansion's garage. Once broke, he established a privately owned business to offer 24-hour scientific services, building ingenious devices for his customers.

Doc and Marty met when the latter was 14, several years prior to the events of the first time travel experiment. Marty, out of curiosity, sneaked into Doc's lab after being warned by his parents to stay away from him. Happy to be revered as 'cool', Doc hired Marty as his part-time lab assistant.

In the original timeline, in contrast with Marty's shy and unassertive father, George McFly, Doc is a supportive and open-minded mentor for Marty. Doc's positive influence in turn allows Marty to mentor George in 1955, which appears to encourage George's later success as a novelist, and help him become a better husband and father. One line in particular, "If you put your mind to it, you can accomplish anything," originates from Doc. Marty repeats it to George in 1955, who repeats it back to Marty in the post time travel 1985.

Doc has been involved with illegal and criminal enterprises (albeit as a means to obtain items for his inventions he could not purchase legally) but he is naive and care-free about the consequences of his actions. He excitedly tells Marty how he cheated Libyan terrorists out of stolen plutonium: "They wanted me to build them a bomb, so I took their plutonium and, in turn, gave them a shoddy bomb casing full of used pinball machine parts!"