At a screening for young people in Washington, Obama called the documentary "The Powerbroker: Whitney Young's Fight for Civil Rights" "a truly a wonderful piece" that is "very moving, very powerful."
She said works such as "The Powerbroker" help people "understand just how much work goes into making change and making things happen."
Obama called it "a perfect day" to watch the film since Wednesday is the 50th anniversary of the March on Washington led by the Rev. Martin Luther King Jr.
"And as you'll see in this documentary, Whitney Young was one of the main organizers of that historic march, which gathered together hundreds of thousands of people of all races and all backgrounds with the important goal of making change," the first lady said. "In fact, Mr. Young spoke on the steps of the Lincoln Memorial just a few minutes before Dr. King gave his 'I Have A Dream' speech.
"But one of the things I want you guys to keep in mind ... is that what this documentary shows us is that there are so many unsung heroes in our history whose impact we still feel today, just regular folks. They're not always going to be the Barack Obamas, the Dr. Kings, the Malcolm Xs.
"For every Dr. King, there is a Whitney Young or a Roy Wilkins or a Dorothy Height, each of whom played a critical role in the struggle for change. And then there are the millions of Americans, regular folks out there, whose names will never show up in the history books.
"I'm talking about the maids who walked miles home from work every night during the bus boycotts in Montgomery. We won't know the names of those men and women, and the young people who faced down fire hoses and police dogs and angry mobs. We know some of those names, but we won't know all of them.
"Each of those people played a critical role in the difficult and often dangerous work of building a better future for all of us."
Obama said she wanted people who see the film to think about "how are you all going to continue what these folks started?"
"What will be your contribution? she asked. "How are you going to make your community and our country safer? Each and every one of you has the power to do that. How are you going to make this entire country more prosperous and more free?"