Buuxi weedhan soo socota: Isagoo doonaya inuu raaco wadadii aabihiis, Johnson wuxuu ogolaansho ka helay General Enoch Crowder si uu uga qayb galo Jaamacadda California (ee Berkeley) halkaas oo uu ku qaatay shahaadada Bachelor of Arts (sharaf) sanadkii 1915 iyo Juris Doctor sanadkii 1916 (labalaabista koorsooyinka si uu ugu qalinjabiyo kala bar waqtiga loo baahan yahay). Waxaa loo wareejiyay Ciidanka Garyaqaanka Guud (JAG), laga bilaabo Maajo ilaa Oktoobar 1916 wuxuu ka hoos shaqeeyey General John J. Pershing ee Mexico oo leh
Pancho Villa Expedition. waxaa loo dalacsiiyay kabtan July 1, 1916, waxaa loo wareejiyay xarunta JAG ee Washington, DC, Oktoobar 1916. Waxaa loo dalacsiiyay sarkaal weyn May 15, 1917, iyo kornayl-ku-xigeen August 5, 1917. Bishii Oktoobar 1917 waxaa loo magacaabay ku xigeenka General Provost Marshal, isla bishaas waxaa loo magacaabay guddiga Wasaaradda Dagaalka ee tababarka militariga (Mareykanka wuxuu galay Dagaalkii Koowaad ee Adduunka bishii Abriil 6, 1917).