Brann was born in
Madison, Maine to Charles M. Brann and Nancy Lancaster Brann. He attended schools in
Gardiner, Maine. He graduated from the
University of Maine in 1898, after which he
studied law. He was
admitted to the bar in 1902 and began a practice in
Lewiston. In the late 1920s he formed Brann & Isaacson with Peter A. Isaacson, a law firm which is still in existence (2010). On March 8, 1902, Brann married Martha "Mattie" Cobb. They were the parents of four children—Donald L., Marjorie, Dorothy L., and Nancy E. Brann participated widely in local and state government: he was the Androscoggin County Register of Probate (1909-1913); a municipal judge (1913–1915); mayor of Lewiston (1915–1917 and 1922–1925); member of the
Maine House of Representatives (1919–1920); and delegate to the Democratic National Convention from Maine (1924, 1936, 1940 and 1944). He also served a term as chairman of the Maine Democratic Party. ==Governor of Maine==