Born in Tbilisi in 1949, Marina Janashia graduated from the Drama Faculty of the Shota Rustaveli Theatre and Film University in 1971. She debuted in the cinema with the short film Nutsa by Alexander Rekhviashvili.

Her most memorable films include Earth, This Is Your Son by Rezo Chkheidze (1980, produced by Georgian Film, The Law of Eternity by Valerian Kvachadze (1982, Georgian Film), The Beginning of the Road by Liana Eliava (1982, Georgian Film), Cucaracha by Siko and Keti Dolidze (1983, Georgian Film), The Lonely Hunter by Keti Dolidze (1989, Georgian Film), A Fold in My Blanket by Zaza Rusadze (2013, Zazarfilm), In Bloom by Nana Ekvtimishvili and Simon Groß (2013, Pollare Film).

Marina Janashia was a member of the Georgian Creative Union of Cinematographers and of the Union of Theatre Workers of Georgia. She received the Georgian Honoured Artist Award in 1981.