He attended Princeton University. After receiving a law degree, he married Mary Dumont or Jane Dumont. She was the daughter of Peter Baptist Dumont (1760-?) and Susanna Van Middleswart of Hillsborough, New Jersey. Together they had the following children:
Sacred to the memory of Frederick Frelinghuysen, Esq. Who died on the 10th day of November, 1820 A.D., aged 33 years. He was called from time in the strength of his days: yet he had lived to good purpose. After receiving the honours of a Graduate in the College of Nassau Hall, he entered upon the study and practise of the law. and soon attained to an elevated place in public esteem and confidence. His intercourse with the world seemed always to be animated by that heavenly principle, which seeketh not her own. He was a friend to the poor and manifested to a life of constant and liberal charities that the children of affliction held a strong claim upon his sympathy and benevolence. In all the social relation he was the delight and ornament of his friends and ... with his memory be precious to them. His mind was early imbued with a solemn sense of religious truth which exhibited its salutary influence in his private and public character. Few entertained a deeper reverence for the principles of the Gospels of Christ. He loved the gates of Zion. As death approached the beams of the Sun of Righteousness shone upon his soul and his and his faith triumphed in the security of the everlasting covenant. He has left the savour of a good name.