John Spencer Letts was born in St. Louis, Missouri.
Letts received a Bachelor of Arts degree from Yale University in 1956 and a Bachelor of Laws from Harvard Law School in 1960.
He was a Reserve Captain in the United States Army from 1956 to 1965.
He was a vice president and general counsel of Teledyne in Los Angeles, California from 1966 to 1973, and was in private practice in Los Angeles from 1973 to 1975 before returning to his previous positions with Teledyne from 1975 to 1978.
[1] On November 7, 1985, Letts was nominated by President Ronald Reagan to a new seat on the United States District Court for the Central District of California created by 98 Stat.