His father was the San Francisco confectioner, George H. Cardinet, Sr., (10/20/1883-11/07/1970). He owned the Cardinet Candy Company, maker of the U-No candy bar.

He married Margaret M. Bowen in 1934; born 06/19/1911, she died in Contra Costa County, CA, 12/07/1992.

Cardinet had one son, George Cardinet III, and two daughters, Maureen Casteel and Michele Tomasulo, all alive in 2007.

Cardinet was instrumental in building the United States National Trails System on the West Coast. He physcially laid out some routes while on horseback (particularly in the East Bay Hills of San Francisco where he lived), and lobbied government officials to provide funding to produce more. His activities in promoting trail-building spread over 50 years, from the 1940s-1990s.