He represented the Latvian SSR in Soviet Team juniors chess championships in Leningrad in 1951 at first board (5½/9).
Zilber would end up homeless on the streets of New York City through most of the 1980s and played chess with strangers in Washington Square Park.
According to Fred Waitzkin's book Searching for Bobby Fischer, IM Zilber was considered the best player in Washington Square Park with the exception of GM Roman Dzindzichashvili, and would leave the park whenever Dzindzichashvili would arrive there.
Details of Zilber's later years are inconclusive – an unconfirmed story states that during a harsh winter he froze to death.
[28] A different theory claims that he is not listed in the Social Security Death Index and could still be alive.