Born on August 4, 1848, in Cortland, New York, Thomas received an Artium Baccalaureus degree in 1870 from Yale University.

[citation needed] At the New York state election, 1885, he ran on the Republican ticket for New York Attorney General but was defeated by the incumbent Democrat Denis O'Brien.

[citation needed] Thomas was nominated by President William McKinley on February 7, 1898, to a seat on the United States District Court for the Eastern District of New York vacated by Judge Asa Wentworth Tenney.

He was confirmed by the United States Senate on February 15, 1898, and received his commission the same day.

[1] Following his resignation from the federal bench, Thomas served as a Justice of the Supreme Court of New York for the Second Judicial District from 1907 to 1918.