Stephen Gaghan was born on May 6, 1965, at Louisville, Kentucky, United States. His parents are Elizabeth Jane Wharton and her first Husband, Stephen Gaghan. He then became the stepson of Tom Hagg. He began his education at Kentucky Country Day School which is a college preparatory school at Louisville. During the school days, he made the school level Assist record for almost three decades as a soccer player in All- State . His Grandfather was a Drama Critic of Variety and Philadelphia Daily News and also News Paper Columnist, Jerry Gaghan. Stephen also has the interest of becoming a Newspaper writer while he set down in writing an article in the year 2001.

He also wanted to become like his grandfather who used to carry a bag with full of letters having the message that if anyone finds him, they have to call his son at the given number. During his school days he was expelled from the school for driving go-cart in the school hall. The critics commented that it was because of the teenage that he took drugs and became addicted and drove in an unrealistic way. Stephen also wrote in a new week article by February 2001 that he was not much different from his fellow student except the fact that he can't stop after taking a few drinks. Further, he could progress through Cocaine, Heroine, and Marijuana and finally freebase and crack.

He also revealed that by 1997 he started getting addicted to drugs. On a Long five-day Weekend, Stephen began to do deal with his drug dealers who all got arrested later. He also added that his dealer, his backup dealer, and his backup- backup dealer got arrested and he was left all alone. He went to the University of Kentucky, a member of Delta Tau Delta Fraternity. During fall 1986 voyage, he was the student of the “Semester at Sea” and began to study abroad. He studied in classes at SS universe and traveled all around the world. In Massachusetts, he studied at Babson College. He began his own company Fallen Empire Inc., which was a catalog company.

For the drama named Traffic, he wrote the Screenplay which received the Award of Best Adapted Screenplay for the year 2000 from Academy Awards. Apart from Traffic, he wrote the Screenplays for some more dramas like Syriana in 2005, Abandon in 2002, Havoc in 2005, Rules of Engagement in 2000 and The Alamo in the year 2004. Apart from cinema industry, he also wrote the screenplay for the Television industry and won several awards which includes The Emmy award for NYPD Blue episode. By 2017, he collaborated with Ubisoft for the direction in play adaption of a famous video game The Division.