Gustas was born on April 4, 1932 in Karceviskiai, a village in what is now the western Lithuanian district of Silute. She spent her early childhood years in Lithuania, but fled to Germany with her mother when the Soviet army occupied the country.

Gustas lived in Berlin, where she co-founded Berliner Malerpoeten, a group of artists and poets, together with Nobel literature laureate Guenter Grass and other like-minded people.

She held numerous solo and group exhibitions, and published several collections of poetry, some of which have been translated into Lithuanian.

At Gustas' request, no funeral will be held. Her cremated remains will be scattered over the Baltic Sea.