Prosecutors had sought to keep Assange jailed as a flight risk while he fights extradition to Sweden on sexual assault charges but the London High Court refused the request.
"It's great to smell the fresh air of London again," Sky News quoted him as saying as he left custody.
"Thank you to all the people around the world who had faith in me and have supported my team while I have been away."
Justice Duncan Ouseley agreed with a decision by a lower court earlier in the week to release Assange, 39, on cash bail and strict conditions on his movements, The Guardian reported.
Assange will be subject to an electronic monitoring device and curfew as conditions of his release.
Assange has denied sexual assault allegations made by two women in Sweden.
"It's an ongoing investigation in Sweden and the prosecutor needs to interrogate him to make a decision on the matter," said Karin Rosander, a spokeswoman for the Swedish prosecution agency.
Assange surrendered to London police last week and was arrested on a European warrant from Sweden where prosecutors want to question him. He was granted bail Tuesday, but remained in jail because the bail was appealed immediately.
Conditions of Assange's bail require him to stay at a supporter's house, report to police daily and wear an electronic monitoring device.
The hearing in London was separate from Assange's role in publishing more than 250,000 U.S. State Department documents and comes as prosecutors in Washington try to build a case against Assange, The New York Times reported.
U.S. prosecutors were looking for evidence that would allow them to charge Assange with aiding an Army intelligence analyst suspected of leaking the information, the Times said. If they find the evidence, prosecutors said they believe they could charge him as a conspirator instead of a recipient of the documents who then published them.