The Academy Award-winning actor learned in the latest episode of the PBS genealogy series "Finding Your Roots" that both his grandfather and great-grandfather -- both Jews -- died at the hands of Soviet secret police.
Moreover, his great-grandmother nearly suffered the same fate, spending five years in a Russian concentration camp before eventually making her way to the United States.
The tale was one Hoffman's late father hid from his family, and learning it left the actor in tears.
"Why did he want to erase all this?" Hoffman muses in the episode.
Maybe, Hoffman says, his dad just wanted to shield his family from the tragedies that had befallen his grandfather, Frank, and great-grandfather Sam Hoffman.
"Who knows," Hoffman said. "My father could have been crying, grabbing his father's leg, saying, 'Daddy, please don't go.'
"My poor dad," Hoffman said.
Hoffman said that learning the story has brought him closer to his Jewish roots.
"People ask me today, 'What are you?' " Hoffman said, tearfully. "I say, 'I'm a Jew.' "
The episode of "Finding Your Roots"
featuring Hoffman, as well as actress Mia Farrow, debuted Tuesday. It's also available online
The show was the focus of controversy
last year when it emerged that its producers had omitted information about actor Ben Affleck's slave-owning ancestors at his request. An internal PBS review found that the show's producers failed to "shield the creative and editorial process from improper influence."