His case, which came after the disappearance of four of his colleagues, sparked outrage in Hong Kong and internationally over fears he was taken against his will by Beijing authorities in December. China has repeatedly said its officials wouldn't do anything illegal.
All five men were involved with publisher Mighty Current and its shop Causeway Bay Books, which sold gossipy titles about China's elite.
In a video interview with Phoenix Television, news website thepaper.cn
and other news outlets, Lee said he went to China to assist police with an investigation and said he was free to return once the investigation had finished.
"It was my personal act. I have never 'been kidnapped' or 'disappeared,' nor have I been coerced or bribed. I think the theory of me 'being kidnapped' or 'disappeared' was completely created out of thin air with an ulterior motive."
Asked why he would travel to China in secret without using official travel documents, Lee said he didn't want others to know he was going help police investigate his colleagues.
Lee, a British passport holder, also said he hadn't sought assistance from Britain and had decided to give up his right to residency. He said he thought of himself as a Hong Konger and Chinese.
"I haven't lived in the UK for the past 20 years, neither have I enjoyed any rights or benefits other British citizens hold. My daughter is currently studying in the UK and her tuition is paid in accordance with international standards," he said.
It was not clear whether Lee was speaking under duress, though some commentators believe this was likely.
"There is every reason to suspect he spoke under duress," said Willy Lam, adjunct professor at the Center for Chinese Studies, at the Chinese University of Hong Kong.
'Illegal book trading'
Lee's appearance came after his associates appeared on television Sunday admitting to "illegal book trading" in China.
The four included Gui Minhai, the owner of Hong Kong publisher Mighty Current.
His fellow booksellers, Lui Por, Cheung Chi-ping and Lam Wing-kee, described him as the ringleader of the group. They said he ordered them to send thousands of "unauthorized" books to mainland China.
"We discussed several times how we could avoid inspection by Chinese officials, such as changing the book covers and using dark nylon bags to carry books so that we could get away with X-ray checks at security checks," said Gui.
It isn't clear if Gui or the others were coerced into making their statements. Gui, who appeared on Chinese television in January confessing to a hit-and-run incident,
also didn't address the allegation that he was the ringleader.
On Monday, a Chinese foreign ministry spokesman said the four suspects "admitted their crimes while being interviewed on television."
Hong Kong police are requesting Chinese authorities confirm the details of what Gui and the others said.
They also said they met with Lee Monday at a guesthouse in mainland China and that Lee had told them he had traveled to China "voluntarily" and had not been kidnapped.
But the Chinese University of Hong Kong's Lam found this hard to believe. Referring to the five detainees, he said it was "really incredible that they would themselves voluntarily return to China using unconventional channels. To return to China to face those charges. It's inconceivable.
"The other publishers and journalists [in Hong Kong] in general are afraid that somehow if they run a file of Xi Jinping or the Chinese party or government, they might face some kind of punishment."
Lee disappeared from Hong Kong at the end of December, sparking mass protests amid claims that he had been detained and spirited across the border by Chinese police, who are not permitted to act in the autonomous city.