A left-handed pitcher and first baseman, Weisenstein began playing baseball at age twelve and he continues to play in the St. Louis Baseball Forever League. He has been pitching in the St. Louis Men's Senior Baseball League since 1982 and every year he has gone to the Roy Hobbs World Series in Fort Myers,Florida. Last year, he played in the first 80 Plus national baseball tournament at Thurman Munson Stadium in Canton, Ohio.

From 1959 to 1996, Weisenstein pitched in the Mon-Clair League for Columbia, Millstadt, and Belleville. He played for Belleville Edwards in 1954 and Mahoney Asphalt in 1955. He was on the Jasper Tile team in 1957.

From 1966 to 1982, he pitched in the Fountain of Youth League in Cahokia, Illinois. He was on the Charlie's team that won 57 consecutive games.

He was a pitcher for Belleville Township High School from 1953 to 1956.

In 1954, Weisenstein was on the Belleville American Legion team that won the Illinois state championship. In 2010, he was inducted into the Belleville American Legion Hall of Fame.

He pitched for the University of Missouri at Rolla from 1957 to 1960.

Weisenstein supports the American Legion baseball program in the St. Louis area, and he also supports the St. Louis Men's Senior Baseball League.

He has supported the Mon-Clair League for many years. In 2016, Weisenstein was inducted into the
Mon-Clair League Baseball Hall of Fame.