an american of swedish heritage, carlstrom was a combat veteran of world war i whose health was damaged during the armed conflict. he saw action in minor leagues with the lawrence club of the new england league before joining the boston red sox in the 1911 season. he appeared with boston in two games on september 13–14 and posted a .167 batting average (1-for-6) without home runs or rbi. as a fielder, he recorded three put-outs with six assists and turned into a double play for a perfect 1.000 fielding percentage.