Pagan was born and raised in South Africa, moving to Ireland when she was 11. She graduated from University College Dublin with a Bachelors in English and Drama, and then a Masters in Drama and Performance.

Pagan started her career in County Wexford Youth Theatre, earning her first professional role in Billy Roche's Lay Me Down Softly, which performed in Wexford, Dublin, Galway and London theatres. Since then Pagan has had a starring role in RTE Storyland's Cuckoo, (which earned her an award for Best Actress in a Drama series in LA Webfest), as well as roles in History Channel's Vikings, and HBO's hit TV series, Penny Dreadful. She continues to work in both theatre and film in London and Ireland.