The ex-political staffer got the reprieve on Monday after a letter from the National Anti-Corruption Commission (NACC) informed him it had abandoned the probe.
It ends part of a marathon saga beginning with officials raiding the 31-year-old's home in June 2024, over allegations he swiped the secret documents from the office of former defence minister Linda Reynolds five years earlier.
The sweep, conducted under an operation dubbed 'Ivanhoe', included seizing a blue moleskin diary, which the government claimed contained eight pages of classified security information.
"The former commissioner decided to take no further action concerning the investigation in Operation Ivanhoe," the corruption watchdog's letter reads.
Lehrmann then sued Special Minister of State Don Farrell and the now former NACC commissioner Paul Brereton, saying the raids were an abuse of the watchdog's power.
He also alleges he was unlawfully forced to give evidence at two secret hearings in October 2024 in Hobart, where he resides, and described the agency's investigation as driven by "frivolous, James Bond-like allegations".
His legal skirmishes with Mr Farrell and Mr Brereton are ongoing.
"The NACC has been a colossal waste of taxpayer money," Lehrmann said in response to the watchdog's letter on Monday.
"Over two years the former commissioner used his powers to personally advance a conspiracy that I was a spy and traitor to the nation, selling defence secrets to foreign countries.
"The NACC needs to be abolished and replaced with nothing."
Lehrmann was accused of foraging for the classified information on the French submarines days after he allegedly raped his colleague Brittany Higgins in then-senator Reynolds' parliament house office, in March 2019.
The rape allegations were found to be proven on the balance of probabilities, by Federal Court Justice Michael Lee in 2024.
That finding was upheld twice by the Full Federal Court and the High Court.
Lehrmann has denied the sexual assault claims, which remain untested in a criminal court.
The ex-Liberal staffer remains party to a second anti-corruption investigation, dubbed Operation Greenough, into whether federal police misused information during their probe into Ms Higgins' alleged sexual assault.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028
8°C