He was nicknamed "Hardrock" as a minor league manager because his teams played in a tough, uncompromising way.

He entered pro baseball in 1915, and, in his only big league season, the war-shortened 1918 campaign, he compiled a 1–5 win–loss mark (.167) and a 3.42 earned run average in ten games and 50 innings pitched for the Philadelphia Athletics.

In 1935, Johnson was promoted to a coaching position with the Cubs by manager Charlie Grimm.

The Cubs won three National League pennants (1935, 1938 and 1945) during Johnson's 15 total years as a coach.

On May 3, 1944, with the Cubs having lost nine of their first ten National League games, he served as interim manager for one game, between Jimmie Wilson and Grimm's second term; Chicago lost to the Cincinnati Reds, 10–4, their tenth defeat in a row.