A few months ago, Reese Witherspoon realized everything had changed.

HBO’s glossy, seven-episode drama, “Big Little Lies” — which Ms. Witherspoon starred in and helped produce — won eight Emmy Awards, including the one for best limited series. From the Microsoft Theater stage in Los Angeles on Sept. 17, to swelling applause, Ms. Witherspoon spoke of how important it was to bring “women to the front of their own stories and make them the heroes of their own stories.”

Not long after that night, she found herself in demand.

“It opened a lot of doors for me,” Ms. Witherspoon said in an interview this past week. “People wanted to be in business with me as a producer in the TV space. My mission was to create television for other women, for other female storytellers that are actresses, other directors and other writers. I think it just clicked in people’s minds.”

Since then, Ms. Witherspoon has transformed herself from an actress increasingly frustrated with the roles she was being offered into a producer with a slate of projects that puts her in the company of series creators like Dick Wolf, Shonda Rhimes and Ryan Murphy.

Last month, HBO ordered a second season of “Big Little Lies,” with Ms. Witherspoon’s production company, Hello Sunshine, among the key companies behind the show. In addition, Apple has bought three Hello Sunshine projects as part of its push to compete with Netflix, Amazon and Hulu in streaming. That amounts to a third of Apple’s TV purchases to date.