William Kessler, along with Philip J. Meathe and Harry Smith established Meathe, Kessler & Associates in 1955.

A number of their early residential designs received AlA citations and the firm's reputation began to grow. This resulted in the firm pursuing larger, more complex projects including commercial, education and public housing work.

In the early and mid-1960s the firm expanded its practice to include more commercial, educational and institutional work. Projects completed during this period include design of the Mount Clements Savings and Loan building (1961), and master planning and the design of several buildings on the campuses of Grand Valley State University and Olivet College in Michigan and the State University of New York, Stony Brook, Long Island. In 1968, however, the same year Kessler was named a Fellow of the American Institute of Architects, Kessler and Meathe dissolved their partnership. Kessler established an independent practice, William Kessler Associates, and Philip Meathe went on to work with Smith, Hinchman & Grylls, where he would eventually become president of the firm.

Kessler's practice continued to realize success over the next several decades largely based on his reputation as a talented designer. The 1970s marked a period of transition for the firm as the practice expanded into the historic preservation market and established a niche restoring historic theaters. The firm completed historic theater restoration projects all over the country and received numerous awards for their work. Throughout the 1970s and 1980s the Kessler firm designed a number of significant projects throughout Michigan including the Center for Creative Studies (1975), the Coleman Young Recreation Center (1976), the Detroit Science Center (1978), the Detroit Receiving Hospital (1980) in Detroit and the State of Michigan Library and Historical Center Building (1988) in Lansing. Outside of the state, the firm also completed major

projects including design of the School of Public Health at Harvard University and the WPRI-TV building in Rhode Island. William Kessler & Associates was recognized for its design work receiving over fifty AlA awards including the prestigious Bartlet Award acknowledging Kessler's effort to eliminate barriers to the handicapped in his design of the Center for Creative Studies.

William Kessler Associates became, Kessler, Francis, Cardoza Architects (KFCA) when the firm was reorganized in 1999. Three years later, at the age 77, William Kessler died. The Kessler, Francis, Cardoza firm ceased operations in 2004