Richardson went on to study at Harvard College and Tulane University. Initially, he was interested in civil engineering, but shifted to architecture, which led him to go to Paris in 1860 to attend the famed École des Beaux Arts in the atelier of Louis-Jules André. He was only the second U.S. citizen to attend the École's architectural division—Richard Morris Hunt was the first—and the school was to play an increasingly important role in training Americans in the following decades.
Richardson returned to the U.S. in 1865. He settled in New York in October 1865. He found work with a builder, Charles, whom he had met in Paris. The two worked well together but Richardson was not being challenged. He had little to do and yearned for more. With no work Richardson fell into a state of poverty looking for more work. One of his first commissions was the william Dorsheimer House on Delaware Ave in Buffalo, NY, which is in the style of the Second Empire with a Mansard roof. This important commission led to many other commissions. The style that Richardson developed over time, however, was not the more classical style of the École, but a more medieval-inspired style, influenced by william Morris, John Ruskin and others. Richardson developed a unique and highly personal idiom, adapting in particular the Romanesque of southern France. His early works, however, were not very remarkable. "There are few hints in the mediocre work of Richardson's early years of what was to come in his maturity, when, beginning with his competition-winning design ... for the Brattle Square Church in Boston, he adopted the Romanesque."
In 1869, he designed the Buffalo State Asylum for the Insane (now known as the Richardson Olmsted Complex) in Buffalo, the largest commission of his career and the first appearance of his eponymous Richardsonian Romanesque style. A massive Medina sandstone complex, it is a National Historic Landmark and, as of 2009, was being restored.
The 1872 Trinity Church in Boston solidified Richardson's national reputation and led to major commissions for the rest of his life. Although incorporating historical elements from a variety of sources, including early Syrian Christian, Byzantine, and both French and Spanish Romanesque, it was more "Richardsonian" than Romanesque. Trinity was also a collaboration with the construction and engineering firm of the Norcross Brothers, with whom the Architect would work on some 30 projects.
A series of small public libraries donated by patrons for the improvement of New England towns makes a small coherent corpus that defines Richardson's style: libraries in Woburn, North Easton, Malden, Massachusetts, the Thomas Crane Public Library (Quincy, Massachusetts), (1880–1882) “generally regarded by architectural historians as the masterpiece of Richardson’s libraries” , the Hubbard Memorial Library (Ludlow, Massachusetts), and Billings Memorial Library on the campus of the University of Vermont. These buildings seem resolutely anti-modern, with the atmosphere of an Episcopalian vicarage, dimly lit for solemnity rather than reading on site. They are preserves of culture that did not especially embrace the contemporary flood of newcomers to New England. Yet they offer clearly defined spaces, easy and natural circulation, and they are visually memorable. Richardson's libraries found many imitators in the "Richardsonian Romanesque" movement.
Among the few stations still extant, these influences are perhaps best illustrated in his Old Colony station (Easton, Massachusetts, 1881–1884). Here he uses the Syrian arch that became a hallmark of Richardson designs for both the porte-cochère and the windows of the main structure. Reminiscent of a courtyard and temple that Morse illustrated from Nikkō in Tochigi prefecture, Japan, the hip roof on wide, bracketed eaves nearly hides the rough stonework below in Shadow. Richardson even included a carved dragon at each end of the beam spanning the arches of windows. The walls "become horizontal planes hovering above one another with bands of windows in between."
Richardson was an early although not the first U.S. Architect to look to Japan, but his train stations "form the earliest sustained application of Japanese inspiration in American architecture, an undeniable precursor to Frank Lloyd Wright's Prairie house designs". As with his libraries, Richardson evolved and simplified as the series continued, and his famous Chestnut Hill station (Newton, Massachusetts, 1883–1884, demolished circa 1960) featured clean lines with less Japanese influence.
Despite the success of Trinity, Richardson built only two more churches, focusing instead on the monumental buildings he preferred, plus libraries, railroad stations, commercial buildings, and houses. Of his buildings, the two he liked best, the Allegheny County Courthouse (Pittsburgh, 1884–1888) and the Marshall Field Wholesale Store (Chicago, 1885–1887, demolished 1930), were completed posthumously by his assistants.
Richardson designed many important single-family residences, but his famous John J. Glessner House (Chicago, 1885–87) is his best and most influential urban house. The Mary Fisk Stoughton House (Cambridge, Massachusetts, 1882–1883), the Henry Potter House (St. Louis, 1886–1887, demolished 1958), and the Robert Treat Paine Estate (aka Stonehurst) (Waltham, Massachusetts, 1886) play that role for suburban and country settings. The Glessner House in particular influenced Frank Lloyd Wright as he began developing what would become his Prairie School houses. With his house for Reverend Percy Browne (Marion, Massachusetts, 1881–82) Richardson revived "the old colonial form (of the gambrel roof) to shape the facade of an artistically ambitious house. Perhaps he used the gambrel to signify the humility appropriate to the profession of his client, but in doing so he sanctioned its use for wealthier patrons and by other Architects. Within three years the crumpled gambrel profile was showing up everywhere" and became one of the notable features of Shingle Style architecture.
Richardson died in 1886 at age 47 of Bright's disease, a historical term for the kidney disorder chronic nephritis. On his last day, he signed an informal will directing the three assistants still remaining to carry on the Business, which was soon formalized as Shepley, Rutan and Coolidge. One Example includes Richardson's design for the Greater Cincinnati Chamber of Commerce Building. Richardson had won the selection process in 1885 and nearly finalized the work, but after his death, his aforementioned successors completed the project.
Richardson's most acclaimed early work is Trinity Church. The interior of the church is one of the leading examples of the arts and crafts aesthetic in the United States. It was at Trinity that Richardson first worked with Augustus Saint Gaudens, with whom he would work many times in the ensuing years. Across the square is the Boston Public Library, built later (1895) by Richardson's former draftsman, Charles Follen McKim. Together these and the surrounding buildings comprise one of the outstanding American urban complexes, built as the centerpiece of the newly developed Back Bay.
After his death, more than 20 other stations were designed in Richardson's style for the Boston and Albany line by the firm of Shepley, Rutan and Coolidge, all draftsmen of Richardson at the time of his death. Many Boston and Albany stations were landscaped by Richardson's frequent collaborator, Frederick Law Olmsted. Additionally, a railroad station in Orchard Park, New York (near Buffalo) was built in 1911 as a replica of Richardson's Auburndale station in Auburndale, Massachusetts. The original Auburndale station was torn down in the 1960s during construction of the Massachusetts Turnpike. The original Richardson stations on the Boston and Albany line have either been demolished or converted to new uses (such as restaurants). Two of the stations designed by Shepley, Rutan, and Coolidge (both in Newton, Massachusetts) are still used by Boston's MBTA (green line) public transit Service.
The largest building complex of HH Richardson's career, Richardson Olmsted Campus in Buffalo, New York, United States was designated a National Historic Landmark in 1986. The first building to display his characteristic style the complex of buildings were designed in concert with the famed landscape team of Frederick Law Olmsted and Calvert Vaux in the late 1800s, incorporating a system of enlightened treatment for people with mental illness developed by Dr. Thomas Story Kirkbride. Over the years, as mental health treatment changed and resources were diverted, the buildings and grounds began a slow deterioration. In 2006, the Richardson Center Corporation was formed with a mandate to save the buildings and bring the Campus back to life through a State appropriation for this architectural treasure. Today, the Richardson Olmsted Campus is being transformed into a cultural amenity for the city, beginning with the now open Hotel Henry Urban Resort Conference Center and 100 Acres: The Kitchens at Hotel Henry, both nestled within the iconic Towers Building and two flanking buildings (about one-third of the Campus). Arriving in 2018, the Richardson Olmsted Campus will also welcome the Lipsey Architecture Center of Buffalo. The remaining buildings have been stabilized pending Future opportunities.
Richardson spent much of his later years in his house in Brookline, Massachusetts, which had a studio attached to ease the strain on his health. The house fell into disrepair and was listed in 2007 as an endangered historic site. However, the house was purchased in March 2008 for roughly $2 million with an amended deed requiring that the building be historically restored. The house is on a hill, where Richardson could supposedly watch construction of the Trinity Church in Copley Square, from his second story window.