Nemat was brought up as a Russian (Eastern Orthodox Christian) in Tehran. Her father worked as a dance teacher, her mother as a hairdresser. She was a high school student when the secularizing monarchy of Mohammad Reza Pahlavi was overthrown by Ayatollah Khomeini's Islamic Revolution. As a student Marina opposed the oppressive policies of the new Islamic government, attended demonstrations and wrote anti-revolutionary articles in a student newspaper. On January 15, 1982, at age 16 she was arrested and imprisoned for her views against the revolution. She was tortured in the notorious Evin Prison well known for atrocities against political inmates, and sentenced to death.

However, she survived because a prison guard named Ali Moosavi rescued her. He used his connections to obtain commutation of her sentence to life imprisonment from which he apparently planned to obtain her release. However, after five months of imprisonment, it became clear that Moosavi had developed an attachment to Nemat and intended to force her to marry him.

Under threats of persecution of her family, and to guarantee her continuing safety, she converted to Islam and married Moosavi. See references for a description of the events to follow, including an audio interview with Nemat herself on the BBC's acclaimed Woman's Hour programme first broadcast in 2007, in which she describes marriage to a man she nonetheless hated, and her experience of being raped by him after the forced marriage.

After 2 years 2 months and 12 days of imprisonment, Moosavi's family obtained her release so that she could come and live with him as his wife. He was later assassinated by a rival faction of prison guards.

Nemat then secretly married Andre Nemat, her teenage love and an electrical engineer. They married in a Christian church.

They escaped to Canada in 1991 and have two sons. Marina worked at the Aurora franchise of the Swiss Chalet restaurant chain, and wrote her life story in 78,000 words. She knew that many victims did not want to talk about their fate.

In 2005 there was an article about her experiences in the magazine Sunday Star. Her book Prisoner of Tehran was published in 2007 by Penguin and is being translated into 13 languages.

However among Iranians there have been some doubts whether the book is her personal experience; also about accuracy and credibility of the details in her memoir. The issue is raised several times by some of the ex-prisoners of Evin at the same period, namely Monireh Baradaran. In a petition that she wrote to the publisher, Penguin Group together with other 24 ex-prisoners she writes:

"We consider the publication of this book of distortions and fiction, an insult to ourselves and the thousands of political prisoners that were executed in the prisons of the Islamic Republic. We consider it our duty to document those horrific events and we strive to do so. (...) The execution scene Ms. Nemat describes is so impossible that it can only be a fiction of the writer's imagination."

Monireh Baradaran who has served in the prison for 9 years writes in a different essay:

"Marina Nemat's depiction of her execution scene seems so fabricated that I can't help but ask myself whether this scene has been stolen from a trivial motion picture. (...) I might not be eligible to make a judgment about the accuracy of Nemat's account of her life before she went to prison or while she was in prison. But the book is so filled with inaccurate information and peculiar tales that the reader loses trust in the narrator right from the very start. My criticism of the book, however, is not merely because of its false, bizarre storyline; it is rather because of Nemat's unrealistic description of prison life. Evin prison is a historic fact. You can't write tall tales about it based on your personal taste or interest."

There have been protests against the letter written by Monereh Baradaran and 24 others by other ex-political prisoners from Iran, including Nasrin Parvaz, who was a prisoner for 8 years . Nasrin Parvaz, who is a writer and has written her own memoir of Evin, has written a ten-page letter in defense of Marina Nemat. In it, Nasrin Parvaz writes (translated from Persian):

"These days if you check some internet sites, you will find hate letters against Marina Nemat and her new book 'Prisoner of Tehran.' Marina was 16 when she was arrested and tortured, and today, she has dared to write of what happened to her, and, suddenly, she is the subject of organized attacks by some individuals and groups. There is a decree against her to silence the victims of the Regime (the Islamic Republic of Iran). (...) People like Marina are not allowed to write in Iran, and, outside the country, these sects intimidate and attack them to cover up the truth. I have to mention that these attacks are limited to the internet." marina

In February 2009, Shahrnoush Parsipour, who is a famous Iranian writer and who was in prison in Iran for close to 5 years, wrote a review of Prisoner of Tehran, and in it she stated (translated from Persian): "Prisoner of Tehran, written by Marina Nemat, probably deserves the most attention and deliberation between all the other books written about the prisons of the Islamic Republic of Iran ... by writing a book that is free from exaggeration, the writer (Marina Nemat) has been successful in conveying the terrifying and medieval conditions of the Islamic Republic's prisons ... I recommend this book to everyone..." (http://zamaaneh.com/parsipur/2009/02/post_234.html)

Marina Nemat was awarded the first Human Dignity Prize in December 2007. This prize is to be given annually by the European Parliament and the Cultural Association Europa 2004. The Human Dignity Prize "celebrates organizations and individuals working for a world free from intolerance and social injustice, a world where fundamental human rights are respected." CNW Group | SLOPEN LITERARY AGENCY | Toronto author Marina Nemat awarded first "Human Dignity" prize by European Parliament; presentation in Milan, Italy, on December 15, 2007The Prize Committee said that Nemat was chosen "because of her strength of character despite her life experiences."