I te wha o ona tau, ka timata a Hannigan ki te puta i roto i nga panui. I neke ia ki Hollywood i te 11 o ona tau. I noho ia ki tona whaea me te haere ki te Kura Tuarua o North Hollywood, i angitu ia ki te whakamatautau mo nga kaihoko i a ia e toro ana ki tana papa i Santa Barbara. I muri i tana haerenga ki te Kura Tuarua o North Hollywood, i haere ia ki te Whare Wananga o California State, Northridge, i reira ia he mema o te Alpha Chi Omega sorority me te whiwhi tohu i roto i te hinengaro. Ko te mahi tuatahi a Hannigan i roto i te kiriata nui ko My Stepmother Is an Alien, he whakaari putaiao puta i te tau 1988; ko tetahi o ona hoa-whetu i roto i te kiriata ko Seth Green, i uru mai ki a ia i muri mai i tana kaitoi o Buffy hei hoa rangatira i runga i te mata. I te 1989, ko tana mahi tuatahi i runga i te raupapa pouaka whakaata i puta mai i te wa i whaaiahia ai ia ki te ABC sitcom Free Spirit.
Ko te 11