Oprah thanked Shriver for her efforts over the past seven years to bring women together.
"To enlighten us and encourage us to keep on striving, keep on standing, to keep on climbing, to keep on questioning, to keep on searching and supporting one another," Oprah said.
Oprah was one of five recipients of the Minerva Award, given to women who make a difference in the world through service to others.
The three-day conference at the Long Beach Convention Center seeks to inspire women to come together to transform themselves and their communities. There were exhibiters, book signings and dozens of prominent speakers taking the stage.
Oprah's best friend, Gayle King, was on a special panel of women, including First Daughter Catherine Schwarzenegger, basketball star Lisa Leslie and singer Jessica Simpson.
Obama heaped praise on military spouses and called on America to support the families of our troops.
Obama told the crowd she has always felt knowledgeable on women's issues, but the questions facing military families, she couldn't answer.
"What do you say at Christmas when the only gift your little girl asks for is for her father to come home?" Obama said. "And when he does come home, are you prepared for those months of readjustment?"
In keeping with this year's theme, "It's Time," Obama said it's time for women to help military families any way they can.
Obama said that it is not enough to be proud and that women need to support these families in their communities.
"You don't have to know much about the military to help," Obama said. "You can help by just doing whatever you do best."
Shriver said when her husband was elected seven years ago, she had to redefine herself.
"I've learned that having the job of first lady is a privilege, a blessing, a joy and an incredible opportunity," she said.
Shriver reflected on her time as California's first lady. She talked about what she had learned and also said it was time to set the record straight on where she was wrong.
"I was wrong to try to talk Arnold out of running for governor seven years ago, and he was right not to listen to me," Shriver said. "The fact is, I didn't want Arnold to run because I didn't like growing up in a political family."
After hearing Shriver and Obama, Jerri Kaplan and her granddaughter left feeling empowered.
"I've heard Maria Shriver before and tears come to my eyes," said Kaplan, an Irvine resident. "Michelle Obama is a phenomenal woman for people to look up to."
"It was really amazing to watch these really important women go up and speak about what they're passionate about," said Jade Ponciano of Manhattan Beach. "
It's that passion the speakers hope will motivate the audience to transform themselves and their communities.
Other speakers included ABC News anchor Diane Sawyer, the Honorable Ruth Bader Ginsburg and the Honorable Sandra Day O'Connor.