The house was named after Jonathan Warner, son-in-law of first owner Archibald Macpheadris.
Born in Portsmouth in 1726, Jonathan Warner followed the mercantile path of his father, Daniel Warner, and owned ships by the 1750s. By 1760, Warner was widowed with a young daughter, Polly. That year, he married Mary Macpheadris Osborne, the cousin of his deceased wife and family friend. Mary was a wealthy widow and heir to the estate of her father, Archibald Macpheadris, which included the brick mansion on Daniel Street, now known as the Warner House. Before the War of Independence broke out, Warner was a member of the King's Council, and during the conflict, the Committee of Safety brought him to an Exeter jail after he refused to sign the Association Test. Like many businessmen who had strong financial ties with English trade, Warner straddled the political fence. Near the beginning of the war, Mary died, and in 1781, he married another wealthy heiress, Elizabeth Pitts, daughter of leading Boston patriot James Pitts and granddaughter of James Bowdoin. While his political allegiance remains a mystery, there is no doubt about Warner's business acumen. After the Revolutionary War, Warner resumed his mercantile ways and later became active in local and state government. He served as moderator for the town of Portsmouth.
In 1810, Elizabeth died, leaving her vast estate to her husband. Warner survived long enough to see the Great Fire of 1813 gut Portsmouth, including the south side of Daniel Street where Warner purportedly had a store. As the town began to rebuild that spring, Jonathan Warner's life was slipping away. He died on May 15, 1814, in the same house he had resided in for 54 years.
The mid-19th century journalist Charles W. Brewster recalled Jonathan Warner in Brewster's Rambles About Portsmouth #25. Brewster wrote:
We well recollect Mr. W. as one of the last of the cocked hats. As in a vision of early childhood, he is still before us, in all the dignity of the aristocratic crown officers. That broad back, long skirted brown coat, those small clothes and silk stockings--those silver buckles, and that cane, we see them still, although the life that filled and moved them ceased half a century ago.
When the Warner House first opened in 1932 as a house museum, the 1716-building was largely unfurnished. The last remaining descendant born in the house had died, and the remaining heirs were selling the stately brick home.
An interested buyer was the Standard Oil Company with the intent to demolish the house and build a gas station; a similar fate had befallen the neighboring John Sherburne House several years earlier. A group of preservationists led by local Edith Greenough Wendell formed the Warner House Association and were able to secure the necessary funds to purchase the house in the spring of 1932, an impressive feat during a then-difficult economic climate. Through the years, Warner descendants have donated items back to their ancestral home, and these cherished possessions now furnish the spacious rooms, illuminating the rich life of the six generations who once called the Warner House home.