Brian Blume was born January 12, 1950, in Chicago, Illinois. Blume began playing chess at age seven, and Gettysburg at age nine. He was fascinated by history in junior high school and was involved in miniature wargaming in high school. Blume married, but later divorced. He worked as a tool and die maker's apprentice for his father's company for five years.
Blume met Gary Gygax at the Gen Con game convention in Lake Geneva, Wisconsin, and later became a partner, with Gygax and Donald R. Kaye, in Tactical Studies Rules (TSR). Blume's father, Melvin Blume, providing the funding to publish the original Dungeons & Dragons boxed set. Blume received a blind mailing in 1975 of the first issue of the monthly newsletter Owl and Weasel from Games Workshop, and he sent Ian Livingstone and Steve Jackson a copy of Dungeons & Dragons in return. Livingstone and Jackson felt that this game was more imaginative than anything being produced in the UK at the time, so they worked out an arrangement with Blume for a three-year exclusive deal to sell D&D in Europe.
After Kaye's death in 1976, his widow sold her shares to Gygax. Gygax – now controlling the whole of Tactical Studies Rules – created TSR Hobbies, Inc., with himself as company president. After encountering financial difficulties, Gygax sold TSR Hobbies to Brian Blume and his brother Kevin, whom Brian got nominated to TSR's board. Gygax originally held 60% ownership of the new TSR, but as part of the reorganization, the new partners had to buy out Kaye's widow and pay other fees; as Gygax was unable to contribute a fair share of these costs, his ownership eventually dropped to 30% of the company, leaving him a minority stockholder.
Blume authored the Dungeons & Dragons supplement Eldritch Wizardry with Gygax in 1976, naming the character Vecna as an anagram of Jack Vance. Blume also worked on The Rogues Gallery. With Gygax, Blume also coauthored the Warriors of Mars miniatures wargame adaptation in 1974, and the Boot Hill role-playing game in 1975. Blume also authored the Panzer Warfare miniatures wargame in 1975.
By 1981, Brian Blume was increasingly unhappy with Gygax's conservative approach to the business, so using their greater stock ownership, the Blume brothers effectively took control of TSR. A year later, Gygax was forced to step down as CEO of the company and was replaced by Kevin Blume and then sent to the west coast to deal with potential TV and movie opportunities. After TSR acquired SPI in March 1982, the Blumes declared that they had "bought assets but not liabilities", but SPI owed money to the printers who refused to release the plates for printing SPI's games until SPI's debts were repaid. The Blumes expanded more successfully into the book trade with series such as Endless Quest. The Blumes also expanded TSR into industries such as toy manufacturing, miniature manufacturing, and even the needlecraft business, and finally worked on expanding into the wider entertainment industry as well. The Blumes expanded the company's role-playing lines with Dragonlance and Marvel Super Heroes.
The Blumes brought in three outside directors from the American Management Association – a lawyer from a large Milwaukee firm, a personnel officer from a Milwaukee area company, and an owner of a company that made medical equipment – to enlarge the Board of Directors to six people; none of the new directors knew anything about gaming, but they always voted with the Blumes.
While Gygax was involved in the making of the Dungeons & Dragons animated television show and exploring the possibility of a film adaptation of the game, he left the day-to-day operations of TSR to Kevin and Brian Blume. By the time he returned to Wisconsin in 1984, the company was $1.5 million in debt. In response, Gygax persuaded the board of directors to fire Kevin Blume. The final vote was 4–1, with Brian Blume abstaining. Gygax persuaded Lorraine Williams to invest in TSR, and hired her to manage the company. Williams dismissed the three outside directors, who had been in place for about two years by that time. In 1985, Brian Blume exercised a stock option to return Gygax to a minority position in the company. The Blumes soon sold their stock to Williams, removing Gygax's controlling stake in the company. Brian Blume left TSR after a bitter struggle with Gary Gygax. Gygax sold his remaining stock and left TSR in 1985.
Blume later worked as a cartographer, mostly on numerous White Wolf supplements.