After attending high school and junior college in his native California, Broglio signed with the independent Oakland Oaks of the Pacific Coast League.

After two seasons in the Giants’ minor league system—when he won 17 games each year—Broglio was traded to the St. Louis Cardinals in October 1958.

Although he led the National League in wins with 21 for the 1960 Cardinals and won 18 for the 1963 Redbirds, Broglio is best remembered as the "other player" in the ultimately lopsided trade that sent future Baseball Hall of Fame outfielder Lou Brock from the Chicago Cubs to the Cardinals on June 15, 1964.

[2] At the age of 17, Ernie graduated from El Cerrito High School and was signed by the PCL Oaks.

[3] In 1953, at the age of 17, Broglio held an earned run average (ERA) of 6.89 in 11 games with 2 wins and 4 losses in his first year on the Oakland Oaks roster.

[3] In his minor league career, Broglio was part of many trades between organizations, playing for the Oakland Oaks, Modesto Reds, Stockton Ports, Dallas Eagles, and Phoenix Giants.

[7] He then would play another 15 years, appear in two more World Series (1967–68), and set the career stolen base record (938, since broken by Rickey Henderson).

[8] The Cardinals organization knew that Broglio's arm would not last much longer, having had twenty cortisone shots in his shoulder in the 1961 season.