A native of Mullingar, Ireland, Algar is the youngest of five children.

[2][3][4] Algar has appeared in films including Conor McMahon's From the Dark,[5] Aoife Crehan's road trip film The Last Right, Lorcan Finnegan's Without Name and the Michael Fassbender-produced Calm With Horses.

[6][7] On television she has appeared in Rose Cartwright's Pure,[8] and as Tania in Desiree Akhavan's The Bisexual.

[10][1] In 2019, Algar played Dinah in Shane Meadows's The Virtues with co-star Stephen Graham.

[12] She has also appeared as Orla Green in MotherFatherSon in 2019 alongside Richard Gere, and as the wife of Travis Fimmel in the Ridley Scott directed American television series Raised by Wolves,[13][14] and as Amber in the Channel 4 television series Pure.