Fernando Valenzuela, the youngest of twelve children, was born in Etchohuaquila, a small town within the municipality of Navojoa in the state of Sonora, Mexico. His birth date is officially listed as November 1, 1960, but during his rookie season in 1981, several commentators questioned his age, guessing him to be significantly older than twenty.
Valenzuela was considered an atypically good hitter for a pitcher. His best year at the plate was 1990—his last year with the Dodgers—when he hit .304 with 5 doubles, 1 home run, and 11 RBI in 69 at-bats. That gave him a 101 OPS+, meaning Valenzuela ranked just above average among all National League hitters that year, including non-pitchers. With 187 hits in 936 career at-bats—roughly two full seasons worth of at-bats for a full-time position player—his career batting average was .200, with 10 home runs, 26 doubles, and 84 RBI. Valenzuela was even used on occasion as a pinch-hitter, batting .368 (7-for-19) in such situations. Twice while with the Dodgers, Valenzuela was called upon to play outfield and first base in marathon extra-inning games in which he did not pitch. He won the Silver Slugger award for pitchers in 1981 and 1983.
In 1981, Valenzuela married Linda Burgos, a schoolteacher from Mexico. Early in his career, Valenzuela and his family spent offseasons between the Mexican cities of Etchohuaquila and Mérida. The couple have four children. One of Valenzuela's sons, Fernando, Jr., played in the San Diego Padres and Chicago White Sox organizations as a first baseman. Since 2006, Fernando Jr. has played minor league baseball in Mexico or in independent leagues.