Richardson had a frequent collaborator in Frederick Law Olmsted who devised the landscaping schemes for half a dozen of his projects, including the Buffalo asylum.

Richardson's work can be seen in many areas around Boston, such as Trinity Church in Copley Square, (1872-1877), Sever Hall, Harvard University (1880), as well as the Allegheny County Courthouse, Pittsburgh, Pennsylvania, (1883 - 1888), and Marshall Field warehouse, Chicago, Illinois (1887).

Following Richardson's early death in 1886 at age 48, the style that he had pioneered was picked up by a variety of other architects whose works are grouped under the name of Richardsonian Romanesque. The style was applied to various types of buildings, churches, public buildings such as city halls, county buildings, court houses, train stations and libraries, as well as residences. The style died out in the first decade of the Twentieth Century. H. H. Richardson has been referred to as the grandfather of modernism.