Assange, 39, was granted bail earlier this week but prosecutors objected to the decision and he remained in jail.
The Australian is fighting extradition to Sweden over sex charges involving two women. He denies the allegations.
Justice Ouseley granted conditional bail at the Royal Courts of Justice and supporters put up 240,000 pounds in sureties.
However, it is not clear yet if he would released from Wandsworth prison on Thursday.
His legal team was organising the sureties required, while there was also the likelihood of new conditions being imposed to the bail.
The whistleblower had appeared confident this morning when he arrived at the high court, giving the thumbs up and a V for Victory sign.
He will now swap his cell at the Wandsworth Prison for Ellingham Hall, a ten-bedroom stately home surrounded by 600 acres of land and trees in Norfolk.
His supporters have offered to put up a surety of 240,000 pounds to guarantee he surrenders to bail.
The appeal was heard at the Royal Courts of Justice in London by Justice Ouseley.
WikiLeaks has published hundreds of sensitive American diplomatic cables, details of which have appeared in various newspapers in the UK and several other countries.
Earlier, the judge banned the use of Twitter to give a blow-by-blow account of Thursday's proceedings from the court.
Assange has received the backing of a number of high-profile supporters including human rights campaigners Jemima Khan and Bianca Jagger, and film director Ken Loach.
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