"I'm going back home, and I look forward to coming back to Japan in the future," a smiling Hilton told reporters before departing on her private jet.
The 29-year-old celebrity socialite had arrived at Narita International Airport, outside the Japanese capital, two days after pleading guilty to a misdemeanor drug charge in Las Vegas. Japan has strict immigration laws that bar entry to those convicted of drug offenses, although exceptions are occasionally granted.
Hilton was to appear Wednesday at a news conference in Tokyo to promote her fashion and fragrance lines. She arrived Tuesday evening, but was stopped at the airport and spent the night at an airport hotel after being questioned by officials.
"I'm really tired," said Hilton, wearing a black baseball cap and a navy sweat suit.
Hilton also abruptly canceled planned appearances in Kuala Lumpur, Malaysia, and Jakarta, Indonesia.
Her publicist, Dawn Miller, said Hilton plans to make the trips at a later date.
"Paris is very disappointed and fought hard to keep her business commitments and see her fans, but she is forced to postpone her commitments in Asia," she said in a statement. "Paris understands and respects the rules and laws of the immigration authorities in Japan and fully wishes to cooperate with them."
A Japanese immigration official said she was denied entry Wednesday after a total of about six hours of questioning over the two days.
The country has taken a tough line with famous figures in the past.
Soccer icon Maradona was initially banned from entering the country during the 2002 World Cup finals for past drug offenses, but was eventually given a 30-day visa as a "special delegate."
The Rolling Stones struggled for years to gain entry to Japan and were eventually allowed in despite drug convictions among the group's members. In January 1980, former Beatles member McCartney was arrested for marijuana possession at Narita airport. He was deported without carrying out a planned concert tour by his rock group Wings.
Kazuo Kashihara, an immigration official at Narita International Airport, said if Hilton had applied for an entry permit farther ahead of her arrival, there might have been a chance for Japan's justice minister to consider an exception in her case. "She just showed up the day after (pleading guilty)," he said.
Just before taking off, Hilton tweeted a message to her fans.
"Going home now. So disappointed to miss my fans in Asia. I promise to come back soon. I love you all! Love Paris xoxo."