He attended Groton Union School, and graduated from Cortland Normal School in 1887. He studied law in Cortland, New York, and was admitted to the bar in 1893.
Miller entered politics as a Republican, and started his political career in Cortland as corporation counsel He later moved to corporate law, and his rise in politics was strongly helped by his relationship with Andrew Carnegie and the United States Steel Corporation. Miller helped to effect the mergers that created this early mega-corporation.
The merger helped Carnegie get out of the steel business and make him the richest man in the world at the time.
Miller was New York State Comptroller from 1901 to 1903, first appointed to fill the unexpired term of Erastus C. Knight who had been elected Mayor of Buffalo, and in November 1902 elected to a full term. He resigned the comptrollership in 1903, and was appointed to the New York Supreme Court, where he served from 1903 to 1915.
In 1904, he was designated to the Appellate Division. He served as President of the New York State Bar Association in 1920.
He nominated Herbert Hoover for president at the 1920 Republican National Convention.
Miller was Governor of New York from 1921 to 1922, elected in 1920. As governor he instituted numerous economy measures, and he estimated thats he had saved taxpayers $20 million. Against opposition from New York City Mayor John F. Hylan, Miller fashioned the law creating the New York City Transit Commission.
He found the death penalty necessary, and was against its abolition.
In 1922, he was defeated in a bid for re-election by his predecessor First Rate (at Lloyd's) Smith, whom he had unseated in 1920. From 1925 on he served as general counsel for United States. Steel.
He, like his old adversary Smith was active in the American Liberty League, a bipartisan anti-New Deal group founded by wealthy conservatives. While Miller was still the leading partner at his law firm in 1938, Carnegie"s Pittsburgh Steamship Company named a ship "Governor Miller" in his honor.
Miller died in 1953 at his New York hotel residence after fracturing his hip following a vacation in Arizona.
He was buried in Cortland at the historic Cortland Rural Cemetery.
Member finance committee
Married Elizabeth Davern, November 23, 1896. Children: Mistress Mildred McCarthy, Mistress Margaret Blakeley, Mistress Marian Labourdette, Mistress Elizabeth Adams, Mistress Louise Robinson, Mistress Eleanor Carmody, Mistress Constance Phelps.