The suspended sentence means she will remain free unless she commits another crime.
Critics have argued that someone working on a supermarket checkout might not have attracted the same level of sympathy from the courts.
When the judge told her she was free to go, Woodward mouthed the words "thank you" and hurried from dock in floods of tears.
Woodward's lawyers said the student - who was supported by university staff at the hearing - had undergone a "sea change" since coming off drugs during the wait to be sentenced and was now a "different woman".
The judge previously took the "exceptional" step of delaying sentencing for four months and ordered her to remain drug free while she stayed at her mother's villa in Milan, Italy.
He suspended the term after James Sturman QC, defending, had urged the judge to give Woodward a conditional discharge because of her "unique vulnerability, remorse and good character".
He said: "She can't even go to a nightclub in London, she's so recognisable."
A prison term could have resulted in her being barred from working as a doctor.
Woodward's barrister told the court in an earlier hearing that her dreams of becoming a surgeon were "almost impossible" as her conviction would have to be disclosed.
But her career options are not entirely blighted as she avoided a prison sentence because, in due course, any community penalty would be expunged.
If she qualified as a doctor and applied for registration, the General Medical Council could consider her application.
The court heard Woodward would not be returning to Oxford this year because of her notoriety.
Sturman said she was considering whether to do a PhD abroad or to look for a research role at another university.
"She has a dilemma: the university remain supportive, they are here today. If she had gone back to Oxford, everyone would have known all about it."
Describing the crime, Judge Pringle said Woodward had met her victim, a Cambridge University student, in October last year.
Woodward was still suffering the effects of a very damaging previous relationship with another who had introduced her to Class A drugs.
When her new partner visited her on December 30, 2016, she had been drinking.
"He tried to discourage your drinking without success," Judge Pringle said.
She became increasingly volatile as the evening progressed, and at one stage the man contacted her mother over Skype for advice on what to do.
This angered Woodward, who started to throw objects around.
"It is clear from the transcript of the 999 call that your partner summoned the help of the police before you picked up a bread knife and struck a blow with it to his lower leg. Two of his fingers also received cuts."
The injured man restrained Woodward, but she tried to turn the knife on herself and he had to disarm her prevent further self-harm.
Judge Pringle continued: "When the emergency services arrived it was abundantly clear that you were intoxicated, deeply distraught and mentally disturbed. You were taken to the police station in a very distressed state.
The man's injuries were relatively minor. Two 1cm cuts to his fingers were treated at the scene and the cut to his leg needed three stitches.
The court heard she attempted suicide in police custody on the night of her arrest and was fired from a job she took at a shop in London 48 hours after being hired when a customer recognised her.
Suspending her sentence, Judge Pringle said: "There are many mitigating features in your case. Principally, at the age of 24 you have no previous convictions of any nature whatsoever.
"Secondly, I find that you were genuinely remorseful following this event and, indeed, it was against your bail conditions, you contacted your partner to fully confess your guilt and your deep sorrow for what happened."
But despite Woodward's intelligence, she was immature and suffered from an emotionally unstable personality disorder, a severe eating disorder and alcohol drug dependence, he added.
"Finally, and most significantly, you have demonstrated over the last nine months that you are determined to rid yourself of your alcohol and drug addiction and have undergone extensive treatment including counselling to address the many issues that you face."
It emerged after her initial court hearing that she had already been warned about drugs by her college just two weeks before the assault.
The 24-year-old posted on social media this year that she had entered The Priory addiction treatment centre in Woking, Surrey. Woodward's older brother was educated at The British School of Milan, formerly known as The Sir James Henderson School, where fees can top £16,000 ($29,700) a year and which is close to her mother's £1 million villa in the Italian village of Sirtori.
College dean the Very Rev Professor Martyn Percy, said Woodward is not currently studying at Oxford, having voluntarily suspended her medical studies.
"The question of her future will now be decided by the university, which has procedures in place when a student is the subject of a criminal conviction."
The court's controversial decision caused outrage on Twitter, with many claiming it was an example of "white privilege".
User @MrTuxed0 wrote: "Lavinia Woodward gets 0 jail time as it 'might hurt her career'? Maybe there's a good reason why drug addicted psychos shouldn't be surgeons."
@anttmcdermottx said: "If Lavinia Woodward wasn't a privileged white girl she would be in prison by now. you can ignore the facts but it's true."
Another user added: "Can we all just agree that if Lavinia Woodward was a man she'd be in jail for domestic violence with no prospect of being a doctor ever?"
