She has been a part of people's lives for more than two decades, hosting her own talk show, publishing her own magazine and launching her own cable-television network.
Oprah Winfrey has succeeded in just about everything she has touched in the past 25 years, but is it enough to call her one of the most influential people of the last two decades?
CNBC turns 25 this year and is asking readers to help come up with the 25 most influential leaders of the past 25 years based on a list of 200 nominees.
Among the entertainment names on the list, Oprah is No. 1 so far in the voting, followed closely by Ted Turner, founder of the cable news channel CNN, and "Star Wars" creator George Lucas. "Harry Potter" author J. K. Rowling and media mogul Rupert Murdoch round out the top five in entertainment.
(Read more: JK Rowling: Nice books, but not that important)
Ilene Cooper, author of "Up Close: Oprah Winfrey," isn't surprised by Winfrey's lead.
"I think she obviously was a dominant figure," said Cooper. "I think she broke a lot of barriers when she started in Chicago in the early '80s. It was unheard of—she was the host of a show, she was African-American, she was a woman and she was overweight."
Over the years, people have been able to identify with Winfrey, according to Cooper, because they witnessed her struggles to succeed in a male-dominated industry.
"25 years ago, the things she was trying were incredibly innovative," she said.