(CNN) After 30 years as a Scientologist, actor Leah Remini turned her back on the church in anger. She's written a book, in which she harshly criticizes her former faith, in part over incidents related to one of its most high-profile figures -- Tom Cruise.

On Friday, she appeared in an exclusive interview on the ABC news magazine "20/20," ahead of the release of her memoir, "Troublemaker: Surviving Hollywood and Scientology," to voice her sentiments.

In November 2013, Miscavige dedicates the massive Clearwater building as the church's new spiritual headquarters.

In November 2013, Miscavige dedicates the massive Clearwater building as the church's new spiritual headquarters.

A headquarters for the Church of Scientology is seen in Clearwater, Florida, in January 2013.

A headquarters for the Church of Scientology is seen in Clearwater, Florida, in January 2013.

Actor John Travolta and his wife, actress Kelly Preston, attend the opening of a Scientology Mission in Ocala, Florida, in May 2011.

Actor John Travolta and his wife, actress Kelly Preston, attend the opening of a Scientology Mission in Ocala, Florida, in May 2011.

An E-meter sits next to Hubbard's book "Self Analysis" in Zurich, Swizerland, in January 2011.

An E-meter sits next to Hubbard's book "Self Analysis" in Zurich, Swizerland, in January 2011.

A volunteer from the Church of Scientology touches an injured woman in Port-au-Prince, Haiti, after the devastating earthquake there in January 2010.

A volunteer from the Church of Scientology touches an injured woman in Port-au-Prince, Haiti, after the devastating earthquake there in January 2010.

Actress Kirstie Alley and actor Tait Ruppert perform during the Church of Scientology's Christmas Stories XIV benefit in December 2006.

Actress Kirstie Alley and actor Tait Ruppert perform during the Church of Scientology's Christmas Stories XIV benefit in December 2006.

Scientology made headlines in June 2005 when Cruise got into a heated debate with "Today" host Matt Lauer over psychiatric drugs. The Church of Scientology's website says that "the effects of medical and psychiatric drugs, whether painkillers, tranquilizers or 'antidepressants,' are as disastrous" as illicit drugs.

Scientology made headlines in June 2005 when Cruise got into a heated debate with "Today" host Matt Lauer over psychiatric drugs. The Church of Scientology's website says that "the effects of medical and psychiatric drugs, whether painkillers, tranquilizers or 'antidepressants,' are as disastrous" as illicit drugs.

Miscavige speaks during the inauguration of the Madrid church in September 2004.

Miscavige speaks during the inauguration of the Madrid church in September 2004.

Confetti rains down as actor Tom Cruise, left, embraces David Miscavige, the leader of the Church of Scientology, at the opening of a new church in Madrid in September 2004. Cruise is one of the world's most prominent Scientologists. "What I believe in my own life is that it's a search for how I can do things better, whether it's being a better man or a better father or finding ways for myself to improve," Cruise told Playboy magazine. "Individuals have to decide what is true and real for them."

Confetti rains down as actor Tom Cruise, left, embraces David Miscavige, the leader of the Church of Scientology, at the opening of a new church in Madrid in September 2004. Cruise is one of the world's most prominent Scientologists. "What I believe in my own life is that it's a search for how I can do things better, whether it's being a better man or a better father or finding ways for myself to improve," Cruise told Playboy magazine. "Individuals have to decide what is true and real for them."

The entrance to the Los Angeles headquarters of the church in March 1998.

The entrance to the Los Angeles headquarters of the church in March 1998.

Hubbard poses for a portrait in New York in January 1982. He died in 1986.

Hubbard poses for a portrait in New York in January 1982. He died in 1986.

Hubbard talks with reporters in his office in 1974. Many groups and individuals have challenged Scientology's legitimacy as a religion. Scientologists have faced opposition from the medical community over the religion's claims about mental health, from the scientific community over its claims about its E-meters and from other religious groups about its status as a religion.

Hubbard talks with reporters in his office in 1974. Many groups and individuals have challenged Scientology's legitimacy as a religion. Scientologists have faced opposition from the medical community over the religion's claims about mental health, from the scientific community over its claims about its E-meters and from other religious groups about its status as a religion.

Hubbard in the south of France in May 1968.

Hubbard in the south of France in May 1968.

Hubbard and his children in December 1959. They are testing a device called an E-meter, which Scientologists say measures the body's electric flow as an auditor asks a series of questions that they say reveals sources of trauma. At the core of Scientology is a belief that each human has a reactive mind that responds to life's traumas, clouding the analytic mind and keeping us from experiencing reality.

After serving in World War II, writer L. Ron Hubbard published a series of articles and then a book on what he described as a new approach to mental health. "Dianetics: The Modern Science of Mental Health" was first published in 1950, and it quickly became a best-seller. In 1954, Hubbard founded the Church of Scientology.

After serving in World War II, writer L. Ron Hubbard published a series of articles and then a book on what he described as a new approach to mental health. "Dianetics: The Modern Science of Mental Health" was first published in 1950, and it quickly became a best-seller. In 1954, Hubbard founded the Church of Scientology.

The Church of Scientology said in a statement to the media that Remini's criticism had more to do with her than with it.

Remini is best known for her role as Carrie Heffernan in the TV sitcom "The King of Queens," which ran from 1998 -- 2007.

Remini: Rigidly strict

Scientology's mission is to save the planet, Remini, whose mother introduced her to the religion as a child, told "20/20."

Actress Leah Remini

That may sound good but has very negative consequences, "because Scientologists view children as spiritual beings, you're not treated as a kid, so you're given a lot of responsibility," she said. "Your ego becomes extremely inflated."

Her mother enlisted her in the Sea Org, a highly disciplined part of Scientology, and she signed a billion year contract with them, she said. Scientologists believe in reincarnation, and Sea Org members are expected to rejoin when they are reborn.

Remini felt she was exploited as youth labor while living in rundown conditions, "20/20" reported. She said she got into unreasonably severe trouble when her boyfriend then touched her in an enticing but not really salacious way.

Remini on Tom Cruise comments

Remini also got written up for comments to and about Tom Cruise during her time as a Scientologist, she said.

Remini was teaching salsa dancing to Cruise and his then girlfriend Katie Holmes. "He was like, forcibly kissing Katie, and I said, 'Hey, get a freaking room.'" Remini got written up for that, she said.

She also disparaged Cruise's famed appeared on "The Oprah Winfrey Show," in which he jumped up on a couch. She got written up again, she said.

Scientology: Remini blaming others

The Church of Scientology shot back at Remini's allegations with a statement criticizing her as blaming others for her own weaknesses and revising events to suit her own agenda.

"She needs to move on with her life instead of pathetically exploiting her former religion, her former friends and other celebrities for money and attention to appear relevant again," the church said in a statement.

Remini has dedicated part of her book to criticizing her own personal faults, saying she pushed people around and was a bad mother, she told "20/20." She said she made the revelations to preempt scathing personal criticism she expected from the church in retaliation to her criticism.