The Harry Potter author told the Leveson Inquiry into press standards she had been forced to take action against newspapers some 50 times over breaches of privacy and misreporting.
Explaining her vigorous attempts to protect her childrens’ privacy, she said she and her husband received phone calls from reporters trying to “blag” personal information.
Rowling, 46, recounted her anger when she found a note that a reporter had slipped inside the bag of her elder daughter when she was in her first year at primary school.
She said: “I unzipped her schoolbag in the evening, and among the usual letters from school and the debris that every child generates, I found an envelope and a letter addressed to me from a journalist.
“The letter said that he intended to ask a mother at the school to put this in my daughter’s bag.
“I can only say that I felt such a sense of invasion. It is very difficult to say how angry I felt that my five-year-old daughter’s school was no longer a place of complete security from journalists.”
Rowling — whose Harry Potter series includes an unscrupulous tabloid journalist called Rita Skeeter — was particularly critical of newspapers that published details about her homes that would allow people to find where she lived.
“I don’t see why it’s in the public interest to know exactly where I live. Clearly I can’t put an invisibility cloaking device over myself and my house, nor do I wish to,” she said.
“I want to live in as normal a way as possible. But it’s not normal for anyone, famous or not famous, for their address to be known to millions of newspaper readers or users on the internet.”
The author, who lives in a remote part of rural Scotland, said reporters “drove her out” of the home she bought in 1997 with the publisher’s advance for the first Harry Potter book.
She told the inquiry she felt like a “sitting duck” after a photograph was published of the house number and street name, and it became “untenable” to remain there.
There were times when she covered her children in blankets to hide them from paparazzi outside her house, the hearing was told.
Rowling also told the inquiry of her fury when OK! magazine published a picture of her elder daughter, then aged eight, in a swimsuit while on holiday on a beach in Mauritius.
She received an apology from the publication but the photograph remained on the internet for months.
“A child, no matter who their parents are, I think deserves privacy. Where children are concerned, I think the issue is fairly black and white,” she said.
The author said she had received extracts from the files of private investigator Steve Whittamore, who was convicted in 2005 of illegally accessing data and passing it to journalists, showing he was trying to find members of her extended family.
Rowling told of she nearly fell victim to a “blagger”.
“This man said to me, ‘I’m from the Post Office, I’ve got a package for you, what’s your address?”’ she said.
“So I began to speak, and then I said, ‘well, wait a moment, you’re from the Post Office, what does it say on the package?’ “And there was a moment’s embarrassed silence and he hung up.”
But her husband, Dr Neil Murray, revealed his address when he received a phone call from someone pretending to be a tax official.
She said: “It was the next day or the day after that he opened his front door at 6am to go to the hospital, and flashes went off in his face and the paparazzi had found him.”
Rowling said the newspaper regulatory body, the Press Complaints Commission (PCC), was “toothless” and supported former Formula 1 boss Max Mosley’s calls for journalists to be forced to contact people before publishing damaging stories about them.
Mosley, 71, told the inquiry that invasion of privacy was “worse than burglary” because break-in victims can replace lost belongings and repair damage.
He was awarded £60,000 in damages at the High Court after taking legal action against the News of the World over a story alleging he had a “sick Nazi orgy”.
Explaining why he went to Europe to seek a law requiring prior notification of potentially defamatory stories, he accused the British government of having been “completely in the thrall” of Rupert Murdoch and other newspaper bosses.
Meanwhile, Sienna Miller told the inquiry that she felt “terrible” for accusing her family and friends of selling stories to the media after journalists obtained intimate information about her by hacking her phone.
The 29-year-old actress, whose films include Layer Cake and Stardust, said: “I felt like I was living in some sort of video game and people pre-empting every move I made, obviously as a result of accessing my private information.”
The hearings continue on Monday with evidence from singer Charlotte Church, broadcaster Anne Diamond and retired teacher Christopher Jefferies, who was wrongly arrested on suspicion of the murder of Joanna Yeates.