In 1835, he began practicing law in Brooklyn with Henry C. Murphy, and soon entered politics as a Democrat.
In 1849, he ran on the Democratic ticket for New York State Comptroller, but was defeated by the incumbent Whig Washington Hunt.
He was a justice of the New York Supreme Court (2nd District) from 1858 to 1869, elected in 1857 to fill the vacancy caused by the death of William Rockwell, and re-elected in 1861 to a full eight-year term.
In 1869, he was elected to an eight-year term on the New York Court of Appeals, but at the same election a constitutional amendment re-organized the Court of Appeals, and Lott remained on the bench only for six months, until July 4, 1870, when the new judges took office.
In 1874, he was made president of the Brooklyn, Flatbush and Coney Island Railway, but resigned a few weeks before his death.