During the first few years of his residence on his estate he took no part in public life. But from the time of his first election to the assembly, in 1726, until his death, in 1751, he was constantly in official position. His career in the assembly was not specially noteworthy. Despite the rivalry of the Morrises, who stood for political views radically opposed to his own, his seat in the assembly seems never to have been imperiled. It was an understood thing in Westchester County for more than half a century that one of the county members should always be a Philipse. He was appointed by Governor Montgomerie ou June 24, 1731, third judge of the Supreme Court of the province, and on August 21, 1733, by the removal of Morris from the chief justiceship and the elevation of de Lancey to that office, he became second judge, continuing as such until his death, lie was also, from 1735 until his death, judge of the Court of Common Pleas of Westchester County. In opposing Chief Justice Morris and siding with de Lancey upon the question of the legality of the Court of Chancery appointed to try the Van Dam case, Frederick Philipse followed the natural bent of his sympathies. It is related in Governor Cosby 's official letter to the home government concerning Morris's famous decision that Justice Philipse, in common with Justice de Lancey, heard k' with astonishment "the abrupt declaration by the chief justice that the Court of Chancery was not a legal tribunal; and this no doubt was a quite faithful representation of his mental attitude on that trying occasion. Whatever may be thought of the conduct of the ambitious de Lancey, Philipse's action was unmistakably ingenuous. It probably never occurred to him to doubt the perfect regularity and sufficiency of a court which had been set over the people at the discretion of the king's governor and his advisers.