A founding member of Platt Byard Dovell White Architects, Paul began practicing architecture in 1977, after a career as a lawyer in which he served as Associate Counsel of the New York State Urban Development Corporation. There he was active in the development of low income housing, and helped to frame the legal basis of the current laws of preservation. His briefs in the Sailors Snug Harbor, Lutheran Church and Penn Central cases supported the process leading to the landmark decision to save Grand Central Terminal. He also served as General Counsel to the Roosevelt Island Development Corporation from 1970 until 1974, and was the principal author of the Lease and General Development Plan of Welfare Island.

As an Associate and Partner of James Stewart Polshek & Partners from 1977 to 1986, Mr. Byard had a role in the preparation of master plans for Carnegie Hall, Boston Symphony Hall and Tanglewood. He joined Charles Platt in 1989 to establish Platt & Byard, Architects; the partnership has since evolved into Platt Byard Dovell White Architects.

Mr. Byard was appointed Director of the Historic Preservation Program of the Columbia University Graduate School of Architecture, Planning and Preservation, in 1999. As Director, Mr. Byard sought to update the curriculum, emphasizing preservation as a creative discipline, clarifying its focus on the understanding, protection and advocacy of the public interest in architectural meaning, and reuniting it with the innovative forces of the Architecture School. Mr. Byard created and helped direct the pioneering Joint Third Year Advanced Architectural Design Studio/Preservation Design Workshop on design with historic monuments, the first of its kind in the nation.

Paul Byard was a prolific writer. He was the author of The Architecture of Additions: Design and Regulation (W.W. Norton, 1998), the first comprehensive critical review of architectural additions as a creative paradigm.

Mr. Byard was a Director of the Architectural League of New York from 1978. As President from 1989 to 1994, he conceived and brought to New York the first American exhibition of the work of the Renzo Piano Building Workshop in 1993. Mr. Byard also served as a Director of the Municipal Art Society of New York from 1968 to 1989, and of the New York Landmarks Conservancy from 1973.