An haifi Thomas Aquinas a cikin katangar Roccasecca, kusa da Aquino, wanda masarautar Sicily ke sarrafata a wancan lokacin (a Lazio na yanzu, Italiya), c. 1225, A cewar wasu marubuta. an haife shi a gidan mahaifinsa, Landulf na Aquino. An haife shi ga reshe mafi ƙarfi na iyali, kuma Landulf na Aquino mutum ne mai hali. A matsayin jarumi a hidimar Emperor Frederick II, Landulf na Aquino ya rike taken mil. [5] Mahaifiyar Thomas, Theodora, tana cikin reshen Rossi na dangin Neapolitan Caracciolo. Ɗan'uwan Landulf Sinibald shi ne abbot na Monte Cassino, mafi tsufa gidan sufi na Benedictine. Yayin da sauran 'ya'yan gidan suka bi aikin soja, iyalin sun yi nufin Thomas ya bi kawun nasa zuwa cikin abbacy; Wannan zai kasance hanyar aiki ta al'ada ga ƙaramin ɗan kudancin Italiya.
Thomas yana da shekaru biyar ya fara karatunsa na farko a Monte Cassino, amma bayan rikicin soja tsakanin sarki Frederick II da Paparoma Gregory na IX ya zube a cikin abbey a farkon 1239, Landulf da Theodora sun sa Thomas ya shiga makarantar generale (jami'a) kwanan nan. Frederick ya kafa a Naples. A can malaminsa a ilmin lissafi, lissafi, ilmin taurari, da kiɗa shine Petrus de Ibernia. A nan ne wataƙila an gabatar da Thomas ga Aristotle, Averroes da Maimonides, waɗanda dukansu za su yi tasiri a falsafar tauhidinsa. Har ila yau, a lokacin nazarinsa a Naples cewa Thomas ya zo ƙarƙashin rinjayar John na St. Julian, wani mai wa'azin Dominican a Naples, wanda ya kasance wani ɓangare na ƙoƙarin da Dominican Order ya yi don ɗaukar mabiyan addini.
Thomas yana ɗan shekara goma sha tara ya ƙudiri aniyar shiga tsarin Dominican, wanda aka kafa kusan shekaru 30 da suka shige. Canjin zuciyar Thomas bai yi wa iyalinsa dadi ba. [11] A yunƙurin hana kutsewar Theodora a zaɓin Thomas, Dominicans sun shirya ƙaura Thomas zuwa Roma, kuma daga Roma, zuwa Paris. Duk da haka, yayin da yake tafiya zuwa Roma, bisa ga umarnin Theodora, 'yan'uwansa sun kama shi yayin da yake shan ruwa daga wani tafki kuma suka mayar da shi zuwa ga iyayensa a gidan Monte San Giovanni Campano.
An tsare Thomas kusan shekara guda a gidan kaso na iyali a Monte San Giovanni da Roccasecca a yunƙurin hana shi ɗaukar ɗabi'ar Dominican da kuma tura shi ya daina sabon burinsa. Damuwar siyasa ta hana Paparoma yin odar a saki Thomas, wanda ke da tasirin tsawaita tsare Thomas. Thomas ya wuce wannan lokacin gwaji yana horar da 'yan uwansa mata da kuma sadarwa tare da membobin Dominican Order.
Iyali sun yunƙura don su hana Thomas, wanda ya ƙudura niyyar shiga Dominicans. A wani lokaci, wasu ’yan’uwansa biyu suka ɗauki hayar karuwa don su lalata shi. Kamar yadda aka haɗa a cikin bayanan hukuma na canonization nasa, Thomas ya kore ta yana riƙe da itace mai kona-wanda ya rubuta gicciye a jikin bango da shi kuma ya faɗi cikin farin ciki na ban mamaki; Mala'iku biyu sun bayyana gare shi yana barci, suka ce, "Ga shi, mun ɗaure ka da umarnin Allah da abin ɗamara na tsafta, wanda daga yanzu ba zai taɓa lalacewa ba. Abin da ƙarfin ɗan adam ba zai iya samu ba, yanzu an ba ku kyauta ta sama”. Tun daga wannan lokacin, Christ ya ba Thomas alheri na cikakkiyar tsabta kuma ya sa ɗamara har zuwa ƙarshen rayuwarsa. An ba da abin ɗamara ga tsohon gidan sufi na Vercelli a Piedmont, kuma yanzu yana Chieri, kusa da Turin.