He was born in Odessa, where his father, Red Fleet Benzion Davidovich Oster (1922-?), a native of Makarov, and a participant in the Great Patriotic War, served. His grandfather David Benzionovich Oster (1898-1944)[8] and his father's younger brother Grigory served in the active army and died at the front. He spent his childhood and youth in Yalta, where his father worked as a turner at the port, and his mother Leia Yakovlevna Oster worked as a librarian at the sailors' club. In 1966 he was drafted into the army, served in the Northern Fleet of the USSR Navy. In 1970 he entered the department of drama at the Gorky Literary Institute in Moscow. He graduated from the Gorky Literary Institute in Moscow in 1982.
Author of many works for children, such as "Fairy Tale with Details", "Papamamalogy", "Adult Education", "Grandmother of the boa constrictor", "Harmful Advice", "Fortune-telling by Hands, Feet, Ears, Back and Neck". He wrote the scripts for the cartoons "38 Parrots", "Gotcha, who bit!", "A Kitten Called Gav", "Junior Monkeys", etc., the feature film "Before the First Blood". Four stories were included in the movie magazine "Eralash".
In the late 1990s, Mikhail Epshtein and Alexander Genis included Grigory Oster in the list of "Who's Who in Russian Postmodernism". In this list of 170 names, Auster is the only children's writer who "made a contribution to the development of Russian literature." At the same time, the writer has never belonged to the socialist realist, dissident, or avant-garde literary camp. According to critics, his aesthetics is characterized by "stylistic eclecticism, subtext, quotation, play of signifiers, irony, parody and stylization".
In 2004, at the suggestion of the Presidential Administration of Russia, he was one of the creators of the site "The President of Russia to the citizens of school age".
From September 7, 2008 to July 18, 2009, together with the singer Glukoza, he hosted the program "Children's Pranks" on STS.
In an anthology of children's literature published in Canada, Grigory Oster with his "Harmful Advice" was the most widely distributed - 12 million copies, while other authors were awarded a maximum of 300-400 thousand
.
