Ruzwana Bashir's election as president of the Oxford Union has been upheld by a tribunal, which held her closest rival guilty of violating poll campaign rules.
After viewing a secretly filmed video and a three-day hearing, the Oxford Union tribunal exonerated her, saying she was a victim of a dirty-tricks campaign.
Bashir, 20, who had won the election with a margin of one vote, had been accused of malpractice.
A Muslim undergraduate, she became the first British-born Asian woman to hold the post in the society's 175-year history.
Three of her opponents now face sanctions for their roles in a "malicious and frivolous" conspiracy against her.
Bashir said she was thrilled to be following in the footsteps of a host of former prime ministers.
She had been disqualified on a technicality after winning the debating society's presidential election last term, but stood and won again last week, only to face a malpractice allegation.
Past presidents of the Union include a roll call of PMs from Gladstone to Edward Heath and Benazir Bhutto of Pakistan.
"I've been exonerated, found completely not guilty, which is all that matters. I'm hugely happy because, obviously, it's been stressful," Bashir said. "I have been a victim of a dirt tricks campaign and ethnicity had nothing to do with it."