Koistinen has an MA in art from the University of Lapland, and additional studies in Sámi and Indigenous research. Currently, she is studying the Inari Sámi language at the Sámi Education Institute (SOGSAKK).

Koistinen has hybrid cultural roots. She was born in Rovaniemi, and her family comes partly from the Inari Sámi culture of Nellim, at the eastern corner of Lake Inarijärvi, and partly from the Torneodalen culture of the Torne Valley. She has also worked as an artist in Siberia, Russia.

Today, Koistinen lives in Äkäslompolo, northwest Lapland. In her artworks, Koistinen aims to relearn ancestral wisdom and values, and reflect her own position in society and her surroundings. Sometimes she feels that she is more of a researcher who processes information through art. One example of her socially engaged art is the installation Hannukainen mining conflict: Voices, with artists Meeri Koutaniemi and Raisa Raekallio. The installation is based on a conflict around reopening an iron ore mine in the village of Hannukainen, located next to Äkäslompolo.

Koistinen pictures the North and its identities and observes the phenomena of everyday life. She is inspired by the meanings of places, and people’s connections to them, stories and dialogue between humans and their surroundings. Lately she has worked in projects that use socially engaged art as a tool of mediation in environmental conflicts, applying research data in the form of art, and encouraging children to engage in outdoor play through environmental arts. In her paintings she reflects the essence of non-human elements of nature.