Rubuta ci gaba don wannan sakin layi - Wani dan asalin Needham, Massachusetts, Arnold ya halarci kuma ya buga wasan hockey a makarantar sakandare a Noble da Greenough School da kuma shirin Boston Junior Bruins kafin ya shiga shirin Ci gaban Kungiyar Hockey ta Amurka don kakar 2009-10. A matakin U-17, Arnold ya kasance kyaftin din ƙungiyar zaɓaɓɓu wanda ya halarci gasar cin kofin ƙasashe biyar a Slovakia; an kira shi mafi kyawun ɗan wasan wasan. A 2010 IIHF World U18 Championships, Arnold ya rubuta maki uku a wasanni shida yayin da Shirin Ci Gaban Ƙungiyar Ƙasa, wanda ke wakiltar Amurka, ya lashe lambar zinare. A cikin 2010 National Hockey League (NHL) Shigar da Shigarwa
, An zabi Arnold a zagaye na huɗu, 108th gaba ɗaya, ta Calgary Flames.