Cook an haife shi ne a Houston, Texas, kuma ya girma a Blue Springs, Missouri. Iyayensa sune Beth Foraker da Stanley Cook. Shi ne tsakiyar 'yan'uwa uku <unk> marigayi Adam Cook ya kasance babba kuma Andrew ya fi ƙanƙanta. Yana da asalin Jamusanci, Irish, da Ingilishi. Sha'awar Cook a cikin kiɗa ya fara ne tun yana ƙarami. Ya fara raira waƙa a aji na biyu, lokacin da malamin kiɗa na makarantar firamare, Mrs. Gentry, ya ba shi wani ɓangare a wasan kwaikwayon makarantar Kirsimeti. Ya ci gaba da yin wasan kwaikwayon a kusan kowane Kirsimeti da shirin PTA. Ya sami guitar na farko, Fender Stratocaster, yana da shekaru 13. Ya kuma shiga cikin ƙungiyar mawaƙa da shirye-shiryen wasan kwaikwayo a makarantar sakandare da makarantar sakandare. A Blue Springs ta Kudu, ya yi wasan kwaikwayo a cikin kiɗa, ciki har da The Music, West Side Story, da kuma Singin 'a cikin Rain.
Beth Foraker da kuma Stanley Cook