Rubuta ci gaba don wannan sakin layi - An haifi Ewell a Georgetown, Gundumar Columbia. An haife shi ne a cikin Yarima William County, Virginia, tun yana da shekaru 3, a wata ƙasa kusa da Manassas da aka sani da "Stony Lonesome". Shi ne ɗan na uku na Dokta Thomas da Elizabeth Stoddert Ewell; jikan Benjamin Stoddert, Sakataren Rundunar Sojan Ruwa na farko na Amurka; jikan Kanar Yakin Juyin Juya Halin Jesse Ewell; kuma ɗan'uwan Benjamin Stoddert Ewell. Ya kammala karatunsa daga Kwalejin Sojojin Amurka a 1840, na goma sha uku a cikin aji na 'yan makaranta 42. Abokansa sun san shi da "Old Bald Head" ko "Baldy". An ba shi izinin zama na biyu a cikin 1st U.S. Dragoons kuma an ci gaba da zama na farko a 1845. Daga 1843 zuwa 1845 ya yi aiki tare da Philip St. George Cooke da Stephen Watts Kearny a kan aikin kulawa tare da Santa Fe da Oregon Trails. A cikin Yakin Mexico da Amurka, yana aiki a ƙarƙashin Winfield Scott, an gane shi kuma ya ci gaba da zama kyaftin don ƙarfin hali a Contreras da Churubusco
Ka yi haƙuri. A Contreras, ya gudanar da bincike na dare tare da injiniya Kyaftin Robert E. Lee, kwamandansa na gaba.