A native of Pryor, Oklahoma, who grew up in Tacoma, Washington, he was the elder brother of "Indian Bob" Johnson, also a major league outfielder.

Roy Johnson batted left-handed and threw right-handed; he stood 5 feet 9 inches (1.75 m) tall and weighed 175 pounds (79 kg).

Unlike his younger brother, who slugged 288 home runs in his 13-year MLB career, Roy was basically a contact, line-drive hitter.

On October 19, 1928, the independently-operated Seals traded Johnson to the Detroit Tigers, launching his decade-long MLB career, where he would be a four-time .300 hitter, and six times finish in the Top 10 among American League (AL) leaders in stolen bases.

Traded by Detroit to the Red Sox in the midseason of 1932, Johnson enjoyed three productive years with Boston, hitting .313 with 95 runs batted in during 1933, however defensively, he again led the AL for the second time in his MLB career by committing 25 errors as an outfielder.