The bill will boost penalties for actions that include taking photos and video of a child without consent and in a harassing manner.
Celebrities such as actresses Halle Berry and Jennifer Garner urged lawmakers to support the bill. Berry testified before several legislative committees that her daughter has been intimidated by aggressive photographers who follow them daily, often shouting as they snap pictures.
The measure also will help protect the children of police officers, judges and others, who might be susceptible to harassment or unwanted attention due to their parents' occupations, de Leon said.
The bill, signed into law yesterday by Governor Jerry Brown, also allows for parents to bring a civil action against violators to seek damages and attorney's fees.
Media organisations, including the California Newspaper Publishers Association, opposed the legislation, saying it was overly broad and could restrict legitimate newsgathering activities.