Since founding Thomas Phifer and Partners in 1997, Thomas Phifer has completed the Museum of Modern Art in Warsaw, an expansion of the Glenstone Museum in Potomac, Maryland, an expansion of the Corning Museum of Glass in Corning, New York, the United States Courthouse in Salt Lake City, Utah, the North Carolina Museum of Art in Raleigh, North Carolina, the Raymond and Susan Brochstein Pavilion at Rice University in Houston, Texas, the Moody Amphitheater in Austin, Texas, two campus buildings for Indiana University, and houses across the United States.

Projects under construction include the TR Warszawa Theatre in Warsaw, an artists' retreat in Maine, and the Wagner Park Pavilion, a key component of the South Battery Park City Resiliency Project in Lower Manhattan. Thomas Phifer is also engaged in private residences in Texas, Maine, and New York.

Since 1997, Thomas Phifer and Partners has received more than thirty honor awards from the American Institute of Architects, as well as numerous national and international citations. His projects have been published and exhibited extensively in the United States and overseas. A monograph on the work of Thomas Phifer and Partners was released in 2010 by Skira Rizzoli.  Thomas Phifer received the prestigious Rome Prize in Architecture from the American Academy in Rome in 1995 and was awarded the Medal of Honor from the New York Chapter of the American Institute of Architects in 2004. He was elected as an Academician of the National Academy of Design in 2011. In 2013, Mr. Phifer received the Arts and Letters Award in Architecture from the American Academy of Arts and Letters. In 2016, he was honored by the New York Chapter of the American Institute of Architects with the President’s Award and by the Sir John Soane’s Museum Foundation. He also gave the 2016 keynote lecture at the Royal Institute of British Architects in London. In 2019, he was awarded the National Design Award in Architectural Design from the Cooper Hewitt Smithsonian Design Museum. In 2022, he was elected as a lifetime member of the American Academy of Arts and Letters. Mr. Phifer is a Fellow of the American Institute of Architects and serves on the boards of the Architectural League of New York and the New York Review of Architecture.

In 2022 the Clemson University of School of Architecture announced a newly endowed fellowship for historically underserved and underrepresented students. The Thomas Phifer Fellowship will support tuition in the School of Architecture for two graduate students for two years in an effort to increase access and broaden a more diverse pathway within the profession of architecture in South Carolina.

Thomas Phifer has served as a visiting professor at numerous architecture schools, including the Columbia Graduate School of Architecture, Planning and Preservation, Cooper Union, University of Southern California, University of Texas, University of Pennsylvania, and Cornell University College of Architecture, Art, and Planning. Mr. Phifer has been appointed the William Henry Bishop Visiting Professor of Architectural Design and the Louis I Kahn Visiting Professor of Architectural Design, both at the Yale School of Architecture. Mr. Phifer received his Bachelor of Architecture in 1975 and his Master of Architecture in 1977, both from Clemson University. In 1977 he studied at the Clemson Architecture Center in Genoa, Italy.