Born in Halberstadt, Germany. The son of a post-office employee, Bormann dropped out of school to work on a farm in Mecklenburg. After serving briefly at the end of WW I, Bormann joined the Freikorps in Mecklenburg.
After his release he joined the NSDAP in Thuringia, and despite his apparent lack of skill and a coarse and brutal manner he become its regional press officer and then business manager in 1928. In October 1933 he became a Reichsleiter of the NSDAP and in November a member of the Reichstag. From July 1933 until 1941 Bormann was personal secretary to Rudolf Hess.
The flight of Rudolf Hess to Britain allowed Bormann to become head of the Parteikanzlei in May 1941 and he proved himself a master of political in-fighting. He developed and administered the Adolf Hitler Endowment Fund of German industry, a huge fund of 'voluntary' contributions by successful business entrepreneurs to the Fuhrer, which Bormann then reallocated as gifts to almost all the top Party functionaries. In addition to administering Hitler's personal finances Bormann controlled all the paperwork and appointments of Hitler. Hitler came to have complete trust in Bormann and the view of reality that he presented.
At the end of the war, after the suicide of Hitler, Bormann left the Fuhrerbunker in Berlin on April 30 1945. Accounts of what happened afterwards vary widely, but it is almost certain he died very soon after leaving the bunker.
He was sentenced to death in absentia at Nuremberg in October 1946. A skeleton found in Berlin in 1972 was officially identified as Bormann and he was formally pronounced dead by a West German court in April 1973.
He was married to Gerda Buch (daughter of the Supreme Party Judge, Walter Buch) and had ten children.