Kirby was also the defense attorney for Preston Tucker, whose development and financing of an advanced automobile, the 1948 Tucker Sedan (also nicknamed the Tucker Torpedo) led to a controversial SEC inquiry and stock fraud trial in 1949. The jury found Tucker and his colleagues not guilty.
Kirby was John MacArthur's attorney. He and Paul Doolen, MacArthur's CFO, suggested that the MacArthurs create a foundation which was endowed by the MacArthur's vast fortune. The legal document, written by Kirby, that created the John D. and Catherine T. MacArthur Foundation was two pages long and written in plain English.
In August 1978, Kirby suggested that the MacArthur Foundation create the Fellows Program. The idea first came to Kirby's attention through George Burch, a doctor at Tulane University. After bringing the idea to the original board members of the MacArthur Foundation, he was instrumental in shaping it.
Kirby also introduced and nurtured other programs that are often seen as hallmarks of the MacArthur Foundation including: