[5][6] After graduating from The Lir, Galligan began her career in stage productions such as The Train with the Rough Magic Theatre Company.

[13] In 2018, she co-founded Chaos Factory, an experimental theatre company alongside Gygax, Venetia Bowe, and Rachel Bergin.

[16] That same year, Galligan began working as an actor-deviser for Murmuration,[17] which debuted with Summertime starring her and Finbarr Doyle.

[21] Galligan and Kostick, having worked on the project since 2017, co-created and performed in Gym Swim Party, a choreography production inspired by his take on the epic in association with O'Reilly Theatre.

[11][23] In her early career, Galligan featured in short films such as Strangers in the Park, Pernicio, Beautiful Youth, and Break Us.

[32] In 2023, she had a main role as Mallory Markum in the dark comedy series Obituary with Siobhán Cullen, which was released on RTÉ in Ireland and Hulu in the US.

[35][36] She also stars in the audible original vampire-apocalypse audio drama Impact Winter: Season 2 by Travis Beacham alongside a full cast.