He played for 17 seasons in the big leagues, primarily with the Phillies and St. Louis Browns. Southworth was a versatile player who could play both first base and the outfield, and he was known for his solid hitting and good baserunning skills. He was a two-time All-Star and finished his career with a batting average of .277 and 1,759 hits.

After retiring as a player in 1931, Southworth went on to manage in the major leagues for 24 seasons. He managed for five different teams, most notably the St. Louis Browns and Boston Braves. Southworth led the Browns to their only American League pennant in 1944, and he also managed the Braves to two National League pennants in 1948 and 1949.

Southworth was a tough and demanding manager, but he was also respected by his players. He was known for his ability to get the most out of his teams, and he is considered one of the best managers in baseball history. Southworth was inducted into the Baseball Hall of Fame in 1982.

The legend of baseball managers also had a brilliant playing career in the MLB. He was a member of the 1926 World Series team.