Ramba uchinyora ndima iyi - Paakasiya Alabama neuto rake duku, Reno akapiwa basa renguva pfupi rokutungamirira Fort Leavenworth Arsenal kusvikira agadzwa kuva brigadier general wevazvipiri mumatsutso a1861. Akaendeswa kuVirginia, akatora mutungamiri we2nd Brigade, Burnside Expeditionary Force, uye nokukurumidza akanga aronga mapoka mashanu. Boka rechipiri rakarwa muMajor General Ambrose Burnside's North Carolina Expedition kubva munaFebruary kusvika munaJuly 1862. Reno akava mutungamiri weboka mu IX Corps, iyo yakanga yava chikamu cheHondo yePotomac. MuNorthern Virginia Campaign, Reno akashinga kupikisa shamwari yake uye waaidzidza naye Stonewall Jackson panguva yechipiri Hondo yeBull Run uye Hondo yeChantilly
. Reno akagadzwa kuva mukuru mukuru musi waAugust 20, 1862. (Kusimudzirwa uku kwakasimbiswa pashure pokufa kwake musi waMarch 9, 1863, uye zuva renzvimbo rakagadzwa saJuly 18, 1862.) Burnside akava mutungamiri wehondo yeArmy of the Potomac's right wing nokuda kwekutanga kweMaryland Campaign munaSeptember, achisimudza Reno kuti atungamirire IX Corps kubva munaSeptember 3.