Rubuta ci gaba don wannan sakin layi - Shiga cikin Sojojin Tarayyar a watan Mayu 1861, ya sami kwamiti a matsayin jami'i tare da 9th New York Volunteer Infantry Regiment, wanda aka fi sani da "Hawkins' Zouaves", kuma daga baya IX Army Corps inda ya yi aiki a karkashin Janar Benjamin Butler a yakin Big Bethel da Hatteras Inlet expedition
Ka yi haƙuri. A shekara ta 1862, ya bi Sojojin Potomac a cikin Janar Ambrose Burnside's Roanoke expedition kuma ya shiga cikin yakin Hatteras Inlet, tsibirin Roanoke, Dutsen Kudancin, Antietam da Fredericksburg. Sau biyu da aka ji rauni a lokacin yakin, Jardine ya ci gaba da zama babban jami'in "gallant conduct" kuma ya umurci 89th New York Infantry Regiment.