 Ramba uchinyora ndima iyi - Johnson akaberekerwa paSalisbury Plantation pedyo neMidlothian yemazuva ano muChesterfield County, Virginia, asi mhuri yake yakakurumidza kutamira kuKentucky. Akapinda United States Military Academy uye akapedza kudzidza pashure pemakore mashanu edzidzo muna 1838. Akapiwa basa rokuva mutevedzeri womutungamiriri wehondo mu6th U.S. Infantry uye akasimudzirwa kuva mutungamiriri wehondo mumakore asingasviki gore. Akashanda muHondo dzeSeminole muFlorida uye ipapo muMadokero. MuHondo yeMexico neAmerica, Johnson akazviratidza paVeracruz, Cerro Gordo, Churubusco, Molino del Rey, uye Chapultepec. Akagamuchira kukwidziridzwa kaviri, kuva kaputeni uye mukuru, munguva yehondo uye akapiwa munondo wemhemberero nehurumende yeVirginia nokuda kwoushingi hwake. Johnson akadzokera kubasa pamuganhu wekumadokero, achishanda muDakota Territory, California, Kansas, uye paUtah Expedition. 