| Lou Johnson | |
| Position: | Pitcher |
| Bats: | Unknown |
| Throws: | Left |
| Birth Date: | November 18, 1869 |
| Birth Place: | Pekin, Illinois |
| Death Place: | Kansas City, Missouri |
| Debutleague: | MLB |
| Debutdate: | September 11 |
| Debutyear: | 1894 |
| Debutteam: | Philadelphia Phillies |
| Finalleague: | MLB |
| Finaldate: | September 26 |
| Finalyear: | 1894 |
| Finalteam: | Philadelphia Phillies |
| Statleague: | MLB |
| Stat1label: | Win–loss record |
| Stat1value: | 1–1 |
| Stat2label: | Strikeouts |
| Stat2value: | 10 |
| Stat3label: | Earned run average |
| Stat3value: | 6.06 |
| Teams: |
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John Louis Johnson (born John Louis Mercer; November 18, 1869 – January 28, 1941) was an American left-handed pitcher who played briefly for the Philadelphia Phillies during the season. Johnson was born in Pekin, Illinois.
In his major league career, Johnson posted a 1–1 record with a 6.06 ERA in four appearances, including three starts and two complete games, giving up 22 earned runs on 44 hits and 15 walks while striking out 10 in innings of work. Johnson died in Kansas City, Missouri at the age of 71.