He was the son of John Lowman (1832–1884) and Fanny (Bixby) Lowman. On September 9, 1893, he married Katherine Harding Smith. He was admitted to the bar, and practiced in Elmira, New York.
He was a member of the New York State Assembly (Chemung Co.) in 1909 and 1910. He was Chairman of the Chemung County Republican Committee from 1912 to 1934. He was a member of the New York State Senate (41st D.) from 1919 to 1924, sitting in the 142nd, 143rd, 144th, 145th, 146th and 147th New York State Legislatures. He was a delegate to the 1924 and 1932 Republican National Conventions.
He was Lieutenant Governor of New York from 1925 to 1926, elected at the New York state election, 1924 on the Republican ticket. At the same time, Democratic Governor Al Smith was re-elected, while his running mate George R. Lunn was defeated. Lowman was the last lieutenant governor of New York who was not the running mate of the elected governor. At the New York state election, 1926, he was defeated for re-election when Al Smith was re-elected with his running mate Edwin Corning.
From August 1, 1927 until the end of the Hoover administration in 1933, he was Assistant U.S. Secretary of the Treasury under Andrew W. Mellon and Ogden L. Mills, and as a notorious "dry" was in charge of the enforcement of Prohibition. A month after taking office, he said: "There are many incompetent and crooked men in the service. Bribery is rampant. There are many wolves in sheep's clothing. We are after them... Some days my arm gets tired signing orders of dismissal." 
Afterwards he was President of the Elmira Savings Bank.
- TIME Magazine on September 19, 1927 (giving middle initial "M.")
-  The tariff imbroglio with France, in TIME Magazine on October 17, 1927
-  TIME Magazine on July 25, 1927
|New York Assembly|
David C. Robinson
|New York State Assembly
Robert P. Bush
|New York State Senate|
Morris S. Halliday
|New York State Senate
James S. Truman
George R. Lunn
|Lieutenant Governor of New York