The 2016 season will be Dean Yamaguchi's 12th year as assistant softball coach at Chaminade University. A graduate of Saint Louis School and the University of Hawai`i, Yamaguchi has two children, son Chason and daughter Shalin "Anuhea", who is a former Silverswords softball player.  Yamaguchi is also employed at the Trump International Hotel on the Waikiki Beach Walk.

During the April 20, 2014 doubleheader at Hawai'i Pacific, Yamaguchi was thrust into the acting head coaching role when an illness forced his brother and Silverswords head coach, Kent Yamaguchi, to be taken to the hospital just minutes before first pitch. Dean Yamaguchi would guide the 'Swords to a 5-3 win in Game 1, the program's first win at HPU in nearly eight years.

Yamaguchi was born in Honolulu and resides in Nu'uanu.