In November 1857, he was elected a justice of the New York Supreme Court to fill the vacancy caused by the resignation of James Mullett. He was re-elected in 1859, and remained on the Supreme Court bench until the end of 1867. He was ex officio a judge of the New York Court of Appeals (8th District) in 1859 and 1867.
In 1865, he ran for the remaining six years of the term of Henry R. Selden on the Court of Appeals, but was defeated by Republican John K. Porter who had been appointed to fill temporarily the vacancy caused by Selden's resignation.
In November 1867, he was elected a judge of the New York Court of Appeals for a term of eight years. Although he was legislated out of office upon the re-organization of the Court of Appeals in 1870, he was the only judge who continued on the Court of Appeals bench, having been re-elected to a 14-year term in May 1870.
He died in office, and was buried at the Angelica Cemetery.
- United States Congress. "Martin Grover (id: G000506)". Biographical Directory of the United States Congress.
-  Candidates for office, in NYT on November 7, 1865
- The New York Civil List compiled by Franklin Benjamin Hough (page 352; Weed, Parsons and Co., 1858)
-  Court of Appeals judges
|United States House of Representatives|
William Spring Hubbell
|Member of the U.S. House of Representatives
from New York's 30th congressional district