on 15 September 1865.
Leonard attended school at Amenia Academy and secured a classical education under a private tutor. He began the study of law at Pine Plains and in 1846 removed to Poughkeepsie and entered the law office of Tallman & Dean. In 1847 he was admitted to practice, and at about same time was appointed Surrogate's clerk. For a short time he was a law partner of Hon. Gilbert Dean, and shortly after the close of the Civil War formed a copartnership with General A. B. Smith, which continued for a period of twenty-five years, and during which they were connected with many prominent and several famous cases. For two terms he filled the responsible position of treasurer of Dutchess County, and for twelve years was a member of Board of Education of the City of Poughkeepsie, serving three years as its president. At one time he was the candidate of the Democratic party for County Judge, and at another for Mayor of the City of Poughkeepsie. For a decade previous to his death, Aug. 30, 1906, in the 85th year of his age, he lived in comparative retirement at his comfortable home, 45 Fifth Avenue, Poughkeepsie, which was presided over by his unmarried and accomplished daughters. The Poughkeepsie News-Press, of Sept. 3, referring to his character, says:
"In the death of Leonard B. Sackett, there passed from earth a man whose long life was a blessing to those who in any way came near to him. He was an old time Democrat in politics. In these days reference to old time Democrats, or old time Republicans, means rather old time associates, old time friends, old time actors in public affairs. Mr. Sackett was an old time Democrat in a far broader sense than any reference to his political beliefs can signify. His was that democracy of character which marked the old time gentleman, whose abilities shone wherever he was, and whose courtesy was as uniform as it was charming. He was brave enough to have opinions and strong enough to defend, and stand up for them, be the storm against or with him. He was so kind as to make friends even with arguments against their cause. He was so plain in his life that pride of opinion, pride of position, pride in any undemocratic form was incompatable with his character.
"Therefore it was that through all the four score years of his life, he was the genial friend, the sunny philosopher, the optimistic acquaintance, and the steady example of good living. He was as true to his friends as he was to himself, and it was not in his nature to betray either. His citizenship was lofty and his ideals pure. He was possessed of that precious wisdom which enables a man to grow old in peace and satisfaction. Prosperity could not mislead him, adversity could not change him. His family inherit the sweet memory of a devoted father in all that the word means. His friends inherit the example of a firm, true, useful life. His county has lost an intelligent, faithful son. His party has lost a devoted defender."
—Weygant, The Sacketts of America
and was recorded in the census as Leonard B Sacket, a lawyer, head of household, a widower, aged 55 and born in New York. Living with him were his unmarried daughters, Laura, 23, and Lilla, 20. Also in the household were Fredrick Loveles, a gardener, and Norah Clear, a servant.