Matt Hazeltine was born August 2, 1933 in Ross, California, located in Marin County, just north of San Francisco.

[2] Hazeltine died in San Francisco on January 13, 1987 of amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's Disease.

He was one of three 1964 San Francisco 49ers teammates who died of ALS, a rare ailment with an incidence estimated at 1 per 50,000 individuals in the general population.

[3] Others 49ers felled by the terminal disease included contemporaries Bob Waters and Gary Lewis and — a generation later — wide receiver Dwight Clark.

[3] Studies have been done examining the use of DMSO, painkillers, and the fertilizer used on the 49ers practice field in Redwood City, California in an effort to isolate a potential chemical connection.