Mr. de Lancey married on the 22d of November, 1820, Frances, third daughter of Peter Jay Munro, of New York, and of Mamaroneck, the distinguished lawyer, (only child of the Rev. Dr. Harry Munro, the last English Rector of St. Peter's church, Albany, N. Y., by his third wife, Eve Jay, daughter of Peter Jay, the first of that name in Rye, (one of whose younger brothers was Chief Justice John Jay) by his wife Margaret, daughter of the Hon. Henry White, of the Council of the Province of New York, and his wife Eve Van Cortlandt, of Yonkers.

While a divinity student Mr. de Lancey held the first services of the Episcopal Church in Mamaroneck ; and with the aid of his father, John Peter de Lancey and Peter Jay Munro, who were its first wardens, founded the Parish of St. Thomas in that village.

After serving for short periods as deacon in Trinity church, and in Grace church, New York, he was invited by the venerable Bishop White of Pensylvania to be his personal assistant in the " Three United Churches " of Christ church, St. Peter's, and St. James in Philadelphia, of which he was also the Rector. Mr. de Lancey accepted this position and removed to Philadelphia, where he continued to reside in the closest and most confidential relations with Bishop White, until the death in 1836, of that great and venerable prelate, the first Bishop of the American Church, consecrated by Anglican Bishops.

During this period, in 1827, in his thirtieth year, Mr. de Lancey was chosen Provost of the University of Pensylvania, that old " College in Philadelphia " founded by Benjamin Franklin; and also received the degree of D.D., from his Alma Mater, Yale College -- being the youngest man upon whom, up to that time, she had conferred that honor.