Whitehead said she was happy to find out that she was grand prize winner, and couldn't wait to come to Los Angeles.
"It was really exciting," Whitehead, 10, said.
Johnson said he was glad to learn he had won too.
"We're going to California," Johnson, 11, said. "I feel great, we get to go on the big field, be on television, it's really exciting."
Prey said his teacher found out he'd won first and gave him the news right away.
"I was very excited," Prey, 11, said. "I was pulled right out of the class I was in, I was like, 'am I in trouble?' and she's like, 'no, you won!'
"It's definitely an honor, I've never been in anything this big, let alone I've never done anything that's slightly noticeable in history, so this is just a huge deal for me," he said.
The Breaking Barriers essay contest is open to children in grades four through six. The contest is a major component of Breaking Barriers: In Sports, In Life, a multi-curricular character education program developed by MLB and Scholastic, Inc., and led by Sharon Robinson.
The Breaking Barriers program is celebrating its 10th year in 2007, and since its inception has reached more than 14 million students across the United States, Canada and the Caribbean.
Students learn about the nine values Jackie Robinson used to overcome the obstacles he faced in his life, such as: citizenship, commitment, courage, determination, excellence, integrity, justice, persistence and teamwork.
Then the students submit an essay about a barrier or obstacle they have faced or are still facing in their lives. In their essays they explain how they use the values exemplified by Jackie Robinson to overcome obstacles in their own lives.
The three grand prize winners wrote about how they dealt with obstacles such as racism, overcoming Attention Deficit Disorder (ADD), and a family member's death. They used values such as commitment, integrity, persistence and determination to overcome these personal barriers.
Whitehead said the value she picked in writing her essay was determination. She wrote about how she is dealing with her father's death.
Whitehead said the determination Jackie Robinson showed is helping her in her life, as well.
"He wasn't afraid to do it, [to keep going]," she said. "I'm determined to keep promises."
Whitehead said it was helpful to write about her experiences, and she was glad to have a chance to meet Sharon Robinson, too.
"I felt really excited, it was like, 'Oh my gosh, I'm meeting Sharon Robinson, the daughter of Jackie Robinson,'" she said.
Johnson said he wanted to enter the contest because it involved baseball.
"I love it, it's my favorite sport," he said.
Johnson said he wrote about all of Jackie Robinson's nine values in his essay.
"I did my report on racism and you need all of those values to overcome racism," he said.
He said he picked the topic because of situations he had faced in his life.
"I was selling candy and this old lady said the 'n' word to me, I just said 'God bless you' and walked away," Johnson said.
Prey wrote about determination, teamwork and excellence in his essay.
"I picked determination because I'm really determined to get over ADD, teamwork, because my family's been helping me completely the whole way through," he said. "Probably excellence would be the one I've used the most, because I'm definitely a perfectionist, I just keep trying to get it right."
Prey said taking part in the contest helped him learn more about Jackie Robinson.
"I didn't know about him much before this, but I read a whole lot of stuff, and he was definitely a great man, even the little I know about him," Prey said.
"All the stuff he had to go through, all the racist remarks that he had to live through," Prey said. "He just kept thinking, 'someday I'll prove them wrong' and he did."