Bruce was born in Staunton Hill, Virginia, and received an academic education at Norwood High School and College in Nelson County, Virginia. He later attended the University of Virginia and graduated from the University of Maryland Law School at Baltimore in 1882. Bruce was admitted to the Maryland bar the same year and commenced law practice in Baltimore, Maryland.

Along with being a lawyer, Bruce was a writer, and received the distinguished Pulitzer Prize in 1917 for his biography of Benjamin Franklin. Bruce began his political career in the Maryland State Senate, serving from 1894-1896, and was appointed as president of the Senate in 1896. He served as head of the city law department of Baltimore from 1903-1908; as a member of the Baltimore Charter Commission in 1910; and as general counsel to the Public Service Commission of Maryland from 1910-1922, at which time he resigned.

Bruce was an unsuccessful candidate for the Democratic nomination for United States Senator in 1916, but achieved election six years later in the election of 1922. Bruce was defeated in the next election in 1928 by Republican Phillips Lee Goldsborough, and resumed the practice of law in Baltimore until 1937, when he retired. He died in Ruxton, Maryland, and is buried at St. Thomas’ Episcopal Church Cemetery in Garrison, Maryland.