Ratkje studied composition at the Norwegian Academy of Music in Oslo under the tutorship of Lasse Thoresen, Olav Anton Thommessen and Asbjørn Schaathun, and got her diploma in 2000.

Maja is a member of SPUNK, a Norwegian improv group, and Agrare, a performance trio consisting of the noise duo Fe-mail and the Swedish dancer Lotta Melin.

She has collaborated with, among others, Jaap Blonk, Lasse Marhaug, Joëlle Léandre, Per Inge Bjørlo, Stian Westerhus, Kathy Hinde, Odd Johan Fritzøe, POING, HC Gilje, Stephen O'Malley, Ikue Mori, and Zeena Parkins.

Ratkje is also an advocate for environmental issues, and is a member of climate action group Stopp oljesponsing av norsk kulturliv (translation: End Oil-sponsorship of Norwegian Arts), and refrains from accepting offers for performances or commissions supported by the oil industry.

[6] Ratkje is a great source of inspiration to new experimental Norwegian musicians like Natalie Sandtorv and Torgeir Standal in The Jist duo.