Complex sentence: Dahlen attended Capuchino High School in San Bruno, California, and played quarterback at San Jose State University, where he graduated from in 1963 (and earned a master's in 1964).
Split into simpler sentences: Dahlen attended Capuchino High School in San Bruno, California. He then played quarterback at San Jose State University, where he graduated from in 1963 (and earned a master's in 1964).