30 Fairfield is located on the SE corner of Commonwealth and Fairfield, with 239 Commonwealth (22 Fairfield) to the north, across Commonwealth, 32 Fairfield to the south, across Alley 433, 240 Commonwealth to the east, and 29 Fairfield to the west, across Fairfield.
30 Fairfield was designed by Peabody and Stearns, architects, and built ca. 1883 as the home of William Gurdon Saltonstall and his wife, Josephine Rose (Lee) Saltonstall. He is shown as the owner of the lot on which 30 Fairfield was built on the 1883 Bromley map, and as the owner on the 1888 map. While the house was being built, they lived at 60 Commonwealth. They also maintained a summer home in Beverly Farms.
William Saltonstall was an East India shipping merchant and then became treasurer of several cotton mills.
Josephine Saltonstall died in January of 1889, and William Saltonstall died in July of the same year. After their deaths, their four children — Robert Saltonstall, Lucy Sanders Saltonstall, John Lee Saltonstall, and Rosamond Saltonstall — continued to live at 30 Fairfield.
Lucy Saltonstall married in June of 1893 to Neal Rantoul, an investment banker, and they made 30 Fairfield their home. Robert Saltonstall, a trustee, married in April of 1904 to Caroline James Stevenson and they moved to Readville. Rosamond Saltonstall married in June of 1906 to Charles Crooke Auchincloss and they moved to New York. John Saltonstall, a stock and bond broker, married in December of 1910 to Gladys Durant Rice and they moved to Beverly.
The Rantouls continued to live at 30 Fairfield and to maintain a summer home in Beverly Farms. The Heirs of William G. Saltonstall are shown as the owners on the 1895, 1898, and 1908 Bromley maps, and Lucy S. Rantoul is shown as the owner on 1912, 1917, 1928, and 1938 Bromley maps.
As originally built, the house had a balustrade on the roof with urns at each corner. In September of 1933, Neal Rantoul filed for (and subsequently received) permission to remove the balustrade, which had become unsafe.
Lucy Rantoul died in November of 1947. Neal Rantoul continued to live at 30 Fairfield and in Beverly Farms until his death in August of 1956.
By 1957, 30 Fairfield was owned by Louis Macey. In March of 1957, he filed for permission to convert the property from a single-family dwelling into ten apartments. The permit was denied, but the denial was reversed by the Board of Appeal. However, the project did not go forward.
By late 1957, 30 Fairfield was owned by the Newman Preparatory School. In December of 1957, it filed for (and subsequently received) permission to convert the property from a single-family dwelling into a school. It subsequently operated its high school for boys at 30 Fairfield.
In December of 1972, the school filed for permission to change the legal occupancy from a secondary school to a degree-granting college. The application was denied and the school’s appeal was dismissed by the Board of Appeal in April of 1973.
In December of 1973, the school filed for permission to convert the property from a school to professional offices. It subsequently abandoned the application.
By 1980, 30 Fairfield was owned and occupied by the Kingsley School. It had been located at 397 Marlborough until about 1975.
Kingsley School reorganized in 1986 as Kingsley Montessori School and, in 2005, it rented several floors at 26 Exeter for its elementary school. The Kingsley preschool remained at 30 Fairfield in 2014.