John Carl Warnecke died on April 17 at age 91 at his family ranch in California's Alexander Valley. Before his career as an architect, he was left tackle for the 1940 Stanford football team that won the Rose Bowl. His firm, John Carl Warnecke & Associates, was once the nation's largest and designed the Hart Senate Office Building and the New Executive Office Building in Washington, D.C. Another significant commission was the Hawaii State Capitol.

While Warnecke's most significant commissions came during the 1960s, his firm's alumni continued important design work well into the current century. The three initial principals of Kohn Pedersen Fox (KPF)—Eugene Kohn, William Pedersen, and Sheldon Fox—were all former Warnecke employees.

According to an obituary in The Press Democrat, Warnecke conducted a "years-long love affair with the widowed Jacqueline Kennedy"—which would be ironic, if true, as he designed the John F. Kennedy gravesite at Arlington National Cemetery.