March 27][1] 1894 in the family of the kapellmeister Abel Zilber and his wife, née Khana Girshevna (Anna Grigorievna) Desson, pianist and owner of music stores.

His sister Leya (married Elena Aleksandrovna Tynyanova, 1892–1944) is the wife of the writer and literary critic Yury Tynyanov, a classmate of Lev Zilber.

His younger brothers: military doctor David Zilber (1897–1967), composer and conductor Alexander Ruchiov (1899–1970) and writer Veniamin Kaverin (1902–1989).

In 1912, Zilber graduated from the Pskov provincial gymnasium with a silver medal and entered the natural department of the Faculty of physics and mathematics of St. Petersburg Imperial University.

He was released after 4 months (possibly, at the request of Maxim Gorky, who was approached by the younger brother of Lev Zilber, writer Veniamin Kaverin, perhaps due to the efforts of his ex-wife Zinaida Yermolyeva).

In 1935–1936 he achieved the creation of the Central Virus Laboratory under the People's Commissariat for Health of the RSFSR and the opening of a department of virology at the Institute of Microbiology of the USSR Academy of Sciences.

[4][3] In 1937, he led the Far Eastern expedition of the People's Commissariat for Health of the USSR to study an unknown infectious disease of the central nervous system.

His brother Kaverin, Ermolyeva, colleagues on the Far Eastern expedition A. K. Shubladze, Mikhail Chumakov, V. D. Solovyov and many others participated in the struggle for his release.

While imprisoned, he served part of his term in camps on the Pechora river, where in the conditions of the tundra he received a yeast preparation against pellagra from the reindeer moss and saved the lives of hundreds of prisoners who died from complete vitamin deficiency.

In March 1944, on the eve of Zilber's 50th birthday, he was released thanks to a letter of innocence addressed to Joseph Stalin[8] and signed by chief surgeon of the Red Army Nikolai Burdenko, Vice President of the USSR Academy of Sciences Leon Orbeli, academician Nikolay Gamaleya, biochemist Vladimir Engelgardt and Zinaida Yermolyeva (the creator of Soviet penicillin and Zilber's ex-wife), who was the initiator of the appeal along with his other colleagues and students.