With his Bermuda-born wife, Ruth Dill, sister of actress Diana Dill, he had four children. Divorced, he started a relationship with his Polish maid, Barbara Piasecka, whom he married in 1971. He signed his final will on April 14, 1983 and died in Fort Pierce, Florida one month later. In accordance with the terms of the will, Barbara Piasecka Johnson inherited his $402,824,971.59 fortune. His six children from his first two marriages contested the will on the grounds that he was not mentally competent at the time he signed the will. They already were given money in trusts, but the legal battle ended with an out-of-court settlement in whuich the Johnson children received an additional $US 42.5 million each.
An avid art collector, Johnson owned an extensive collection of old-master paintings and drawings.
Children of John Seward Johnson I and Ruth Rapalje Neilson Dill (1903-1987):
On October 30, 1944, J. Seward Johnson created six Trust funds, one for each of his children. Basically the same, each trust was principally funded with 15,000 shares of Johnson & Johnson common stock, the present day market value of which is very substantial.
Seward John's son by his wife Ruth is the sculptor John Seward Johnson II. His daughter, Diana Melville Johnson and her husband Bertram R. Firestone are renowned owner/breeders of Thoroughbred racehorses.