Brian was born in Englewood, New Jersey, to Charles and Myra Daley. He has an older brother, David, and younger sister, Myra. He graduated from Northern Valley Regional High School of Old Tappan, NJ, in 1965. He then joined the army and served a year-long tour of duty in Vietnam.

After the army, he attended Jersey City State College, now New Jersey City University, majoring in media. During this time, he wrote his first novel, The Doomfarers of Coramonde. He went on to write the first Star Wars spin-off novels, The Han Solo Adventures. Han Solo at Stars' End, the first book of the trilogy, was a New York Times bestseller. Daley also adapted the original Star Wars film trilogy as a series of radio dramas for National Public Radio.

Daley also wrote under the pseudonym Jack McKinney with his good friend of 20 years, James Luceno. Together, they wrote over 20 Robotech novels and collaborated on the Black Hole Travel Agency series. Luceno is responsible for editing the 1,600-page manuscript of Daley's GammaLAW quartet, which was published posthumously. Daley and Luceno were also amongst a team of writers for the 1986 television cartoon series The Adventures of the Galaxy Rangers.

Lucia St. Clair Robson, an author of historical fiction, was Daley's partner of 14 years.

Daley died in Maryland of pancreatic cancer on February 11, 1996, only hours after celebrating the completion of production on the Return of the Jedi radio drama with the cast and crew. The show is dedicated to his memory.