Yossi Cohen gave details about the theft of Iran's nuclear archive.
The warehouse raid in 2018 ferried tens of thousands of documents out of the country to Israel.
He also hinted at Israeli involvement in the destruction of Iran's nuclear facility at Natanz, and the assassination of a nuclear scientist.
Cohen retired as the head of Mossad last week.
He spoke to journalist Ilan Dayan on Channel 12's Uvda documentary programme, which was broadcast on Israeli television on Thursday night.
Israeli Prime Minister Benjamin Netanyahu appointed Cohen as Mossad chief in late 2015. He joined the agency in 1982 after studying at university in London, and told the programme he had had "hundreds" of passports throughout his career.
The most revealing moments in the interview were about the theft of Iran's nuclear archive.
Netanyahu revealed the stolen files at a press conference in 2018, which he said proved Iran once covertly tried to make nuclear weapons and had secretly retained the know-how - an allegation Iran denied.
Cohen said in the interview that it took two years to plan the operation. In total 20 Mossad agents were involved on the ground - none of whom were Israeli citizens, the journalist Ilan Dayan said.
The spy chief watched the operation from a command centre in Tel Aviv. Agents broke into a warehouse and had to crack more than 30 safes, he said. As images of the trove appeared on screen, "there was incredible excitement for us all," he said, as quoted by The Times of Israel.
All operatives survived the raid and are well, he added, although some had to be extracted from Iran.
Israel has spoken openly about taking those tens of thousands of documents. But Cohen also hinted at Mossad involvement in other operations long rumoured to have been the work of Israeli agents.
Nuclear facility also target of Israeli operation
Early in the interview he spoke about the Iranian nuclear facility at Natanz.
Iran said that sabotage caused a fire at the uranium enrichment site in July 2020. A day after revealing new equipment in April this year, officials again said it had been sabotaged and had suffered major damage. Iran accused Israel of "nuclear terrorism" over the incident.
Cohen told Dayan that he knew the site well, and that he could take her to the cellar "where the spinning centrifuges are located". He then added: "Those that used to spin. Nowadays, the cellar doesn't look like it used to."
And he also spoke about Mohsen Fakhrizadeh. Iran's top nuclear scientist was assassinated on a road outside Tehran last November - an attack Iran publicly blamed on Israel.
The ex-Mossad chief did not confirm or deny involvement in the death. But he said the scientist was a target "for many years", adding that his scientific knowledge concerned the agency.
"If the man constitutes a capability that endangers the citizens of Israel, he must stop existing," he was quoted as saying, but added that someone could be spared "if he is prepared to change profession and not harm us any longer".