"I don't know what it is like to be picked on for being gay, but I do know what it is like to grow up feeling that sometimes you don't belong. It is tough," said Obama, referring to his own youthful search for happiness.
Obama said in the video that he was saddened by the deaths of a number of young people who were bullied and taunted for being gay.
"As a parent of two daughters it breaks my heart," Obama said in the video for the "It Gets Better Project" which is designed to convince gay, lesbian, bisexual and transsexual youths they can become secure in their identity and find happiness and a future.
"You are not alone, you didn't do anything wrong," Obama said in the forceful message delivered directly to camera.
"You didn't do anything to deserve being bullied. There is a whole world waiting for you filled with possibilities," he said, calling on despairing youths to reach out for help.
US Secretary State Hillary Clinton has also recorded a message for the "It Gets Better" website, saying recent deaths were a reminder that Americans had to work harder to "overcome bigotry and hatred."
"I have a message for all the young people out there who are being bullied -- or who feel alone and find it hard to imagine a better future.
"First of all, hang in there and ask for help, your life is so important to your family, your friends and to your country," Clinton said.
More than 10 million hits have been recorded on 2,000 videos on the ItGetsBetterProject.com website and YouTube, according to organizers, in just four weeks since the campaign was set up.
In one of the highest-profile recent cases, two undergraduates at a US university were arrested after a fellow student they allegedly filmed during a gay encounter, and then broadcast on the Internet, killed himself by jumping into the Hudson River in New York.
The tragic incident appeared to be the latest instance of a growing trend of sophisticated technology and social networking sites being used to give old-fashioned bullying a vicious new twist.
Source: AFP American Edition