Na fanau ma ola aʻe McKinnon i le taulaga o Long Island o Sea Cliff, Niu Ioka i le aiga o Laura Campbell, o se matua aʻoaʻo, ma Michael Thomas Berthold, o se tusiata fale. E toʻatasi lona tuafafine laʻitiiti, Emily Lynne. Na maliu lona tama ina ua 18 ona tausaga. A o tamaititi, na taalo McKinnon i ni mea faifaaili. Na amata ona taina le piano ina ua 5 ona tausaga, o le cello ina ua 12 ona tausaga, ma aʻoaʻo ia te ia lava pe faʻafefea ona taina le kitara ina ua 15 ona tausaga. Na faauu o ia mai le North Shore High School i le 2002, ma mai le Iunivesite o Columbia i le 2006 ma se tikeri i le fale faʻafiafia, lea na ia faʻavaeina ai se vaega faʻafiafiaga, Tea Party, lea na taulaʻi i le faʻafiafiaga faʻafiafiaga. I Columbia, na ia taʻalo ai i le tolu Varsity faʻaaliga: V109 "Dial for Deadline", V110 "Off-Broadway" ma
Tausamiga o le Ti