Charles Gwathmey (June 19, 1938 – August 3, 2009) was one of the most celebrated American architects of his generation, a principal of Gwathmey Siegel & Associates and one of the famed "New York Five." In the Flatiron District, his firm designed 240 Park Avenue South, a 17-story residential condominium completed in 2009, the same year Gwathmey died.
Known for rigorous modernism and a sculptural sense of form, Gwathmey gave 240 Park Avenue South a distinctive curved-glass corner and unusually wide spaces between its windows, which he envisioned as room for residents to hang art. The building stands at the corner of East 19th Street as a refined, late-career statement from an architect who shaped American design for four decades.
| Full name | Charles Gwathmey |
| Born / Died | June 19, 1938 / August 3, 2009 |
| Profession | Architect, principal at Gwathmey Siegel & Associates Architects |
| Active in Flatiron | 2000s (240 Park Avenue South, completed 2009) |
| Known for | Gwathmey Siegel & Associates, the 1992 Guggenheim Museum addition, member of the "New York Five" |
| Key Flatiron location | 240 Park Avenue South, at the corner of East 19th Street |
| Notable legacy | Designed one of his final New York buildings, 240 Park Avenue South, completed the year of his death |
Who Was Charles?
Charles Gwathmey was born in Charlotte, North Carolina, in 1938, the son of the painter Robert Gwathmey and the photographer Rosalie Gwathmey. He trained at the University of Pennsylvania and Yale. He also designed a now-iconic house and studio for his parents in Amagansett, New York, early in his career. It was a small modernist building that announced a major talent.
In 1968, Charles co-founded the firm that became Gwathmey Siegel & Associates with Robert Siegel. The following year, Gwathmey was identified as one of the “New York Five,” a group of architects championed for their return to pure, geometric modernism rooted in the work of Le Corbusier. Over the following decades, the firm designed museums, university buildings, corporate headquarters, and private houses across the country.
Perhaps his most visible commission was the 1992 addition to Frank Lloyd Wright’s Guggenheim Museum in New York, a delicate and much-debated task of building alongside a masterpiece. By the time of his death in 2009, Gwathmey was widely regarded as one of the leading American architects of the previous half-century.
Charles Gwathmey's Connection to the Flatiron District
Late in his career, Gwathmey turned to a cluster of residential towers along Park Avenue South, helping reshape the corridor just north of Union Square and Gramercy Park. His firm’s 240 Park Avenue South, at the northwest corner of East 19th Street, was completed in 2009, the same year Gwathmey died. That made it one of the last of his New York buildings to be realized in his lifetime.
The 17-story condominium reflects his lifelong design discipline. Rather than wrapping the building in floor-to-ceiling glass like so many of its contemporaries, Gwathmey gave it a contemporary masonry character, with a rounded corner base and deliberately wide piers between the windows so residents could display artwork on interior walls. The result is a building that feels both modern and grounded in the historic fabric of the Flatiron and Union Square area.
Legacy and Impact
240 Park Avenue South stands as a poignant late chapter in Gwathmey’s career, completed in the final months of his life. It anchors a stretch of Park Avenue South that has become some of Manhattan’s most desirable residential real estate, and it demonstrates how a rigorous modernist could design a high-rise that respects the texture of an older neighborhood.
Gwathmey’s broader legacy extends far beyond any single building. As a member of the “New York Five” and the lead architect of the Guggenheim addition, he helped define the trajectory of American architecture from the late 1960s onward. His Flatiron-area work gives the neighborhood a direct link to that legacy. 240 Park Avenue South is a building by a genuine master, finished at the very end of his life.
Completed in 2009, the year Charles Gwathmey died, 240 Park Avenue South stands as one of the final New York works by one of America's great modern architects.
Key Facts Worth Knowing
- 1938: Charles Gwathmey was born in Charlotte, North Carolina, the son of painter Robert Gwathmey.
- 1969: Gwathmey was named one of the "New York Five," a group of influential modernist architects.
- 1992: He designed the addition to Frank Lloyd Wright's Guggenheim Museum in New York.
- 2009: 240 Park Avenue South was completed, with 51 residences across 17 stories.
- 2009: Gwathmey died on August 3 in New York City, the same year his Park Avenue South building was finished.
FIND THEIR LEGACY TODAY
- 240 Park Avenue South — Gwathmey Siegel's 17-story condominium at the corner of East 19th Street, distinguished by its curved-glass corner base.
- Park Avenue South, 19th–24th Streets — the residential corridor Gwathmey's firm helped redefine in the 2000s.
- Solomon R. Guggenheim Museum, Fifth Avenue — Gwathmey's celebrated 1992 addition, a short trip uptown for anyone exploring his wider body of work.
Explore More of Flatiron's History
→ 240 Park Avenue South — Our full review of the Gwathmey Siegel–designed condominium at the corner of East 19th Street.
→ Flatiron District Architecture Guide — The architectural legacy of the neighborhood where Gwathmey's late-career residential tower stands.
→ Flatiron District History — How Park Avenue South evolved from a commercial corridor into one of Manhattan's premier residential streets.
→ Flatiron District Walking Tour — Walk the Park Avenue South corridor Gwathmey's firm helped reshape in the 2000s.
In Plain English
Charles Gwathmey was a celebrated American architect and a principal of Gwathmey Siegel & Associates. In the Flatiron District, his firm designed 240 Park Avenue South, a 17-story condominium completed in 2009, the year he died. It is known for its curved-glass corner and wide spaces between windows for displaying art.
Frequently Asked Questions About Charles Gwathmey
Q: What did Charles Gwathmey design in the Flatiron District?
A: Gwathmey's firm, Gwathmey Siegel & Associates, designed 240 Park Avenue South, a 17-story residential condominium at the corner of East 19th Street, completed in 2009.
Q: Who was Charles Gwathmey?
A: Charles Gwathmey was a leading American architect, a principal of Gwathmey Siegel & Associates, and one of the "New York Five." He was also known for the 1992 addition to Frank Lloyd Wright's Guggenheim Museum.
Q: When was 240 Park Avenue South built?
A: 240 Park Avenue South was completed in 2009, the same year Charles Gwathmey died, making it one of his last New York buildings to be finished in his lifetime.
Q: What is distinctive about the design of 240 Park Avenue South?
A: The building features a rounded corner base and intentionally wide spaces between its windows, which Gwathmey designed so residents could display artwork rather than maximizing glass like many contemporary towers.
Q: What was the "New York Five"?
A: The "New York Five" was a group of five architects identified in 1969, including Charles Gwathmey, known for a return to a pure, geometric modernism influenced by Le Corbusier.