Jackson, 49, of San Francisco, a political consultant, had been held at the Oakland jail under an arrangement with the U.S. Marshals Service since his arrest by FBI agents on March 26.
He walked out of the Glenn Dyer Detention Facility at 6:35 p.m., according to Amy Merriweather, a spokeswoman for his lawyers.
U.S. Magistrate Nathaniel Cousins granted Jackson the release on a $250,000 bond at a hearing in San Francisco this morning but stayed his order until 5 p.m. to give prosecutors a chance to appeal.
Assistant U.S. Attorney William Frentzen, who earlier this week called Jackson a "one-man crime wave," had told Cousins that prosecutors planned to appeal to a federal district judge to have Jackson held in custody while awaiting trial.
But the court docket does not show any filing of an appeal, and Merriweather said the defense attorneys did not receive a notice of appeal.
Jackson, who served as San Francisco Unified School District Board of Education president in the mid-1990s, is one of 26 people, including suspended state Sen. Leland Yee, D-San Francisco/San Mateo, who were charged in a wide-ranging criminal complaint last week.
Jackson is accused of funneling campaign contributions to Yee in exchange for political favors to donors; selling guns and ballistic vests to an undercover FBI agent who was posing as a Mafia member; and conspiring with his 28-year-old son, Brandon Jackson, and another man to distribute drugs.
He is also charged with conspiring with Yee in a proposed $2 million international arms deal and aiding in the arrangement of a proposed murder-for-hire. The gun deal and murder plot, which were allegedly discussed with the agent posing as a Mafioso, were not carried out.
A grand jury indictment to replace the complaint is expected soon and Jackson, Yee and most of the other defendants are due to be arraigned on the indictment before a different magistrate in San Francisco on Tuesday.
Frentzen argued unsuccessfully today and in an earlier hearing on Tuesday that Jackson should be kept in custody because he is a flight risk and danger to the public.
Defense attorney James Brosnahan said Jackson had no criminal record and was a community activist who hoped to aid San Francisco by helping to arrange jobs and housing.
"He's not going anywhere," the attorney told Cousins today.
Cousins agreed, saying, "A significant factor is that Mr. Jackson is a lifelong member of the community with significant ties to the community."
Jackson's bail includes a $50,000 property bond to be posted by his mother, Annie Scott, for the value of her mobile home in Texas.
Scott and Jackson's companion, Pamela Gilmore, also both signed additional unsecured bonds in which they promised to be liable for the entire $250,000 if Jackson fails to show up for court hearings.
Cousins ordered Jackson to submit to electronic monitoring and remain in home confinement in the California Street apartment he shares with Gilmore except for meetings with his lawyers, work, medical appointments or religious services.