Bennett emerged to cheers from dozens of supporters who had gathered outside the prison in the eastern town of Mutare.
Tsvangirai had tapped Bennett to become deputy minister of agriculture but was arrested on terror charges a month ago, just as the new cabinet was being sworn in.
Instead of being sworn in with other cabinet members, he was accused of possessing arms for the purposes of banditry, terrorism and sabotage.
Prosecutors tried to keep him in prison but the Supreme Court approved his bail on Wednesday after weeks of legal wrangling.
"There are gross human rights abuses behind those walls," Bennett told journalists and party supporters at the provincial headquarters for Tsvangirai’s Movement for Democratic Change (MDC) after his release.
"People are suffering… They are having a single meal a day.
"Five people died while I was inside and it took the prison officers 4 to 5 days to remove the bodies. The situation behind there is pathetic.
"There are no vehicles to take prisoners to court. Cells are overcrowded," he said.
Bennett, who once ran a coffee plantation until his farm was seized by President Robert Mugabe‘s government, appeared clean-shaven and healthy, wearing a white T-shirt with beige shorts.
He was visibly moved by the warm reception from MDC supporters as he headed to the party’s office.
He was required to pay $5 000 bail, to surrender his travel documents and to report to the Harare Central Police Station three times a week.
The charges against him stemmed from an alleged plot to assassinate Mugabe in 2006.
At the time, Bennett fled to neighbouring South Africa to escape arrest, but other MDC officials, including the new co-minister for home affairs Giles Mutsekwa, were cleared by the courts which discredited the alleged plot.
"It’s a huge relief that he has been freed. It’s a case which should have never gone to court in the first case as there was no substance," Innocent Gonese, the MDC’s chief parliamentary whip told AFP.
"The relief is that he is out of that hell of a place, as our prisons are hell on earth."
Bennett said that he planned to travel to the nearby town of Buhera to pay his respects to Tsvangirai’s wife Susan, who was killed in a car crash last Friday. She was buried in Buhera on Wednesday.
Afterwards he said he would travel to the capital Harare to be reunited with his family.
Bennett’s case has become a symbol of the challenges facing the new unity government, which has brought together Tsvangirai with long-time rival Mugabe.
The MDC has accused Mugabe’s government of orchestrating deadly political attacks against their supporters.
Tsvangirai claims to have survived 4 assassination attempts, and has suffered a severe beating at the hands of security forces.
The unity government was meant to end the political violence, but Bennett’s arrest immediately cast doubt on the durability of the coalition with 85-year-old Mugabe.