Both brothers attended Pepperdine University, with Gordon later going on to graduate from the United States Merchant Marine Academy.

Their older brother, John Dee Hahn, became a civil service employee in 1930 and also was a clerk in the Los Angeles County Superior Court.

In 1987, Dale Hahn, James and Janice's cousin, became a judge of the San Mateo County Superior Court, and would retire in 2004.

In 1988, the Baldwin Hills State Recreational Area was renamed to the Kenneth Hahn State Recreation Area to honor his preservation efforts there; later on, the Los Angeles County Hall of Administration was renamed to the Kenneth Hahn Hall of Administration in 1992.

[11] The 103rd Street/Watts Towers station on the A Line of the Los Angeles Metro Rail was previously named 103rd Street/Kenneth Hahn in his honor.