William J. Groo, of Middletown, Orange County, New York, was born in the town of Neversink, Sullivan County, New York, September 9, 1831, his ancestors being among the first settlers of that town. His father was a farmer who died when William Jay was but a year and a half old. His grandfather, Samuel Groo, was a Revolutionary solder.
William Jay was employed on the farm during the summer and went to a district school in the winter until his seventeenth year, when he attended a select school for one year, and completed his studies at the Monticello Academy. In 1852 he commenced the study of law with General A.C. Niven, then the leading lawyer of Sullivan county, and was admitted to the bar in 1855. While a law student he was appointed deputy county clerk, and at the death of the clerk succeeded to the office. He was selected district attorney in the fall of 1857 and served three years. In 1861 he was appointed by Governor Morgan one of the three commissioners of public accounts for the State and resigned after serving two years.
Mr. Groo was a Douglas Democrat at the outbreak of the war, but immediately espoused the Union cause and became identified with the Republican Party; he was a delegate to the national convention of that party in 1864 and voted for the renomination of Abraham Lincoln. In 1866 he moved from Monticello to Middletown, Orange county, and was elected in the fall of 1868 special county judge of that county.
Failing to induce the Republican Party to espouse Prohibition, Judge Groo became a Prohibitionist in 1873. He was the party’s candidate for governor in 1876, and for judge of the court of appeals in 1886, when he was the only candidate on the ticket and received 36,114 votes, the largest number ever polled up to that time for a prohibition Party candidate. He has been twice the chairman of the Prohibition State convention, three times a delegate to the national conventions, and was chairman of the New York delegation in 1888e
Mr. Groo became a member of the Methodist Episcopal Church soon after his removal to Middletown, and materially assisted in the erection of the town’s finest church. He was the first lay delegate chosen from the New York annual conference to represent it in the general conference of 1872.
Ever since his admission to the bar, Judge Groo has been in active practice and has had many important suits, both civil and criminal.
— Data from An Album of Representative Prohibitionists (1895)