The former editor of Rupert Murdoch's now-defunct Sunday newspaper spoke of her difficulties becoming a mother during her "roller-coaster" first marriage, and her affair with Andy Coulson, her former deputy, who is standing trial alongside her.
Giving evidence for a second day in the trial at the Old Bailey court in London, Brooks talked about royal stings and the huge deals for exclusives with celebrities such as football icon David Beckham.
Brooks edited Britain's biggest-selling newspaper between 2000 and 2003, before running its daily sister title The Sun until 2009.
The 45-year-old appeared close to tears and asked for a break as she began talking about her fertility treatment, which was halted by the flurry of work around the 2003 invasion of Iraq.
"It was a tough year for us. Basically, life was put on hold for Iraq," she said of her marriage with TV actor Ross Kemp.
Brooks divorced Kemp in 2009 and later that year married her second husband, Charlie Brooks - also a co-defendant - with whom she has a two-year-old daughter born via a surrogate mother.
Brooks admitted to having had periods of "physical intimacy" with Coulson in 1998, from 2003 to 2005 and finally in 2006.
Coulson, her News of the World deputy, succeeded her as its editor and later became Prime Minister David Cameron's media chief.
"My personal life was a bit of a car crash for many years," Brooks told the court.
"It's probably very easy to blame work but the hours were very long and hard and you got thrown together in an industry like that. It was wrong and it shouldn't have happened but things did."
The court has seen an emotional letter from her to Coulson, written in February 2004, which police found on her computer.
Brooks said it was probably written "after a few glasses of wine" and was unfinished and never sent.
She denied claims that she and Coulson were in a relationship for six years.
"It's not true," she said. "I know that's what the police and prosecution say, having analysed the letter," which referred back to 1998.
The letter read: "You are my very best friend. I tell you everything, I confide in you, I seek your advice, I love you, care about you, worry about you.
"Without our relationship in my life, I am really not sure how I will cope."
'Fake Sheikh' royal sting
Turning to her work, Brooks gave examples of "expensive" one-off payments for exclusive "buy-ups" with celebrities.
She said former England captain Beckham was paid "about 1 million pounds ($1.7 million, 1.2 million euros)" for exclusive rights to publish excerpts from his autobiography.
Brooks also detailed the way the News of the World handled a story on Sophie, Countess of Wessex - the wife of Queen Elizabeth II's youngest son Prince Edward.
It involved investigative reporter Mazher Mahmood and his "Fake Sheikh" alter ego, used for numerous stings to trap big-name targets.
Brooks said she did not know that private investigator Glenn Mulcaire was contracted to the News of the World during her editorship. He was later jailed in 2007 for hacking voicemails.
Asked by her defence lawyer Jonathan Laidlaw if she knew anything about Mulcaire's 92,000 pounds-a-year contract, Brooks replied: "No, not at all."
She said that her "sign-off level" for payments in 2000 and 2001 was around 50,000 pounds, so it should have been brought to her attention by her news editor Greg Miskiw. He has pleaded guilty to conspiring to hack phones.
Brooks also said it was "quite normal" for a newspaper to hire private detectives to trace people.
She said spearheading the campaign for "Sarah's Law" at News of the World had "defined my editorship".
The law, eventually introduced in 2011, means parents can find out from the police if a person who has contact with children is a child sex offender.
Brooks is charged with conspiring in voicemail hacking, conspiring to bribe public officials and two counts of trying to cover up her alleged crimes.
She, Coulson and six other defendants deny all the charges against them.
The case, expected to run into May, was adjourned until Tuesday.