Katherine Diamond is currently Partner in Charge of Design for Siegel Diamond Architects in Los Angeles, California, a fifteen person, 100% woman-owned architectural partnership with a design portfolio of institutional, commercial, and residential projects. She earned her Bachelor of Architecture degree from The Technion, the Israel Institute of Technology in 1978, and is a registered architect of California and Israel.

Diamond served as 1993-1994 President of the Los Angeles Chapter of the American Institute of Architects (AIA), becoming that chapter's first woman president in its then 99-year history. She was President of the Los Angeles-based Association for Women in Architecture (AWA) for two consecutive terms from 1989 to 1991. She chaired the joint AIA/LA + AWA Committee which organized the Los Angeles installation of the National AIA exhibit "That Exceptional One" and chaired the Exhibit Task Force that created "Women in American Architecture, 1888-1989: a Historic, Contemporary, and Southern California Perspective" that accompanied the "That Exceptional One" exhibit when it traveled to museum sites in California. She serves as the Vice President/President Elect of CWED, California Women in Environmental Design.

Diamond served as design consultant to the architects of the Los Angeles Airport Air Traffic Control Tower and Base Office Building, and as designer of four Elevated Light Rail Stations for the Los Angeles/Long Beach Metro Blue Line, which won the Los Angeles Beautification Award in 1994.