Ask Stanley Nelson about the key to his longevity as a documentary filmmaker and he doesn’t hesitate with his response: “Luck.”

Nelson is the director-producer behind such recent films as “Miles Davis: Birth of the Cool,” which premiered at Sundance last year and is now part of PBS’ “American Masters” series, 2015’s “The Black Panthers: Vanguard of the Revolution” and 2017’s “Tell Them We Are Rising: The Story of Black Colleges and Universities.”

On the latest episode of the Variety podcast “Strictly Business,” Nelson discusses the luck factor in his long career, and the many paths that documentarians pursue to fund projects that are almost always purely driven by passion rather than dreams of hitting it big at the box office. The environment for independent filmmakers has definitely improved, thanks to the explosion of content and platforms.

“There are so many different funders and so many different outlets for documentary film. That’s made it easier for those like myself who are established,” Nelson says. “Now we’re called content providers. All of a sudden you’re a coveted entity. Ten years ago, people wouldn’t even take your calls.”

Nelson was steered into the documentary realm after he knocked on the door of another Harlem-based filmmaker, William Greaves, when Nelson was fresh out of film school at the City University of New York. He talked his way into a six-month apprenticeship with Greaves, which set him on the path to making his first film, “Two Dollars and a Dream,” about pioneering African American businesswoman Madame C.J. Walker.

Greaves was an important mentor for Nelson at a time when there were few prominent African American filmmakers focused on nonfiction narratives. Nelson has tried to return the favor and extend that same lucky break to others through his Firelight Films banner, which has a nonprofit arm, Firelight Media, that runs a Documentary Lab program that offers mentoring and project help for promising filmmakers from diverse backgrounds. This year, Nelson added the William Greaves Fund to help mid-career filmmakers get that all-important second or third project off the ground.

Nelson, who is a 2002 recipient of the coveted MacArthur Foundation “genius” grant, admits to having a little bit of “naivete” about the level of commitment that the Firelight Media projects would require, particularly in fundraising. But as a dedicated docu helmer, Nelson is no stranger to patching together various sources of funding to realize a dream.

Launching the Firelight Media “required two leaps of faith — the first one was whether there were enough filmmakers out there with great projects,” Nelson says. “That’s proven to be true and more so. We didn’t realize that to have an ongoing lab, it means you’re constantly fundraising. It has to keep going.”

“Strictly Business” is Variety‘s weekly podcast featuring conversations with industry leaders about the business of entertainment. A new episode debuts each Wednesday and can be downloaded on iTunes, Spotify, Google Play, Stitcher and SoundCloud.