Lyndon was the son of the late James Lyndon and Ella Schmidt Lyndon. His grandfather, the late James H. Lyndon, was a sheriff in Santa Clara County during the 1800s as well as a postmaster and mayor of Los Gatos. Lyndon's great-uncle was the late John Lyndon, who founded the Lyndon Hotel, which once stood at the corner of S. Santa Cruz Avenue and W. Main Street. The Lyndon Plaza shopping center stands there today.

A graduate of San José State University with a bachelor's degree in biology, Lyndon worked as a model and social worker in San Francisco in his younger years and as a clerk and greeter at the Sainte Claire Hotel in downtown San Jose. He later was a social worker in the emergency room and outpatient clinic at Santa Clara Valley Medical Center. Upon his 1977 retirement, he earned a merit award from the Santa Clara County Board of Supervisors.

Lyndon enjoyed reading, watching videos, displaying photographs of his family and friends and writing and telling stories about the history of San Jose and Los Gatos. His friends recall him as someone with a great sense of humor who was never without a pad of paper and a pen.

Survivors include cousins Dorothy Enos, Suzanne Cistulli, Charlene Silva, Kenneth Hardy and Jeanne, Thomas, John, William and Mary Ellen Guraro, all of San Jose, as well as numerous other cousins throughout California. He is also survived by his closest friends, Bill Wulf of San Jose and Marion Ackerman of Santa Clara.

Memorial services have been held, with interment at Santa Clara Mission Cemetery. Donations can be made to ARIS of Santa Clara County, 380 N. First St., San Jose, 95112, or to the Billy De Frank Lesbian & Gay Community Center, 938 The Alameda, San Jose, 95126.