Sheehan was born in Leeston and grew up in Canterbury, Pōrangahau in the Hawke's Bay, and Christchurch.

Her music featured in the film Once Were Warriors, and in the television series Shortland Street; Home, Land and Sea; and Takatapui.

Her doctoral research was titled The Sound of Identity Interpreting the Multi-dimensionality of Wāhine Māori Through Audio Portraiture.

[7][8] Sheehan has worked at Ngā Pae o te Māramatanga research centre, and was head of the postgraduate programme at Auckland University of Technology's School of Art and Design.

[3] In 2024 the Royal Society Te Apārangi awarded Sheehan the Te Koponui Maori Research Award "for her innovative scholarship, focused on audio portraiture and sonic practices that has elevated the voices and identities of wāhine Māori".