While practicing architecture in New York, Hubert designed the Hotel Chelsea, later to become a well-known residence for actors, writers, musicians and other artists.
[5] His great-grandfather, Charles Antoine Colomb Gengembre, both an architect and civil engineer, supervised the building of the first railway from Liverpool to Manchester.
[10] During World War I Frohman served in the ordnance construction section of the Army and was stationed in the Washington, D.C. area.
[12] The great majority of Frohman's life and work, however, would be dedicated to the construction of the Washington National Cathedral,[nb 1] on which he labored for more than fifty years.
[21] He described it as, “a more beautiful crypt than any I had ever seen abroad; the most satisfying example of church architecture in America.”[22] So taken was he by the cathedral that in signing the visitor register he included a small prayer in code.
[23] Following military service in World War I Frohman moved from Pasadena to Boston to continue his architectural practice.
[24] In 1919 Frohman began making preliminary sketches for revisions of Bodley's designs at the invitation of the Bishop of Washington, The Right Reverend Alfred Harding.
[24] Although adhering to Bodley and Vaughan's original plan in its essence, Frohman made substantial refinements to the initial blueprint.
[11] Although continuing to climb the scaffolding several times a week to inspect the ongoing work,[6] in March 1971, at the age of 83 Frohman retired.
[38] Only in September 1990 would the west end he redesigned be dedicated, completing construction of all principal features of the church's interior and exterior structure, although minor embellishment is expected to continue for years.
[39] A Roman Catholic, Frohman's body was interred in the Chapel of St. Joseph of Arimathea on the crypt level of the National Cathedral by special dispensation of the Archdiocese of Washington.
The inscription on the bay wall reads, in part: “From the deep well of faith sprang devotion to perfection; A graceful witness in this Cathedral Church; To his steadfast spirit and; The prayer his genius sought to record in all his work.”[40]