AMNA NAWAZ: Anna Deavere Smith is well known for her acting in films and TV, including on "The West Wing" and "Nurse Jackie."

She's also made an impact as a playwright, creating her own style of theatrical dramas that explore aspects of American life.

Now she's doing something new, looking back at her own family history.

Senior arts correspondent Jeffrey Brown met with Smith recently in Philadelphia for our arts and culture series, Canvas.

ACTOR: You must sit perfectly seated.

JEFFREY BROWN: A photograph for the 1843 wedding of Basil and Mary Biggs, real-life figures who lived in Maryland and later Gettysburg, Pennsylvania.

ACTOR: I'm getting married to a wonderful girl.

That makes me smile.

JEFFREY BROWN: Now imagined for the theater by their great-great-granddaughter, Anna Deavere Smith.

ANNA DEAVERE SMITH, Playwright and Actress: Because this is the one about my family.

JEFFREY BROWN: A renowned playwright and actor of our time... HENRY LOUIS GATES JR., Harvard University: Of all the stories that we uncovered, we saved the most remarkable one for last.

JEFFREY BROWN: ... who learned of the extraordinary life of Basil Biggs, including his work on the Underground Railroad, on an episode of "Finding Your Roots," the PBS program hosted by Henry Louis Gates Jr.

ANNA DEAVERE SMITH: While slavery existed, he was an active agent in the Underground Railroad, helping fugitives to freedom.

Oh, this is amazing.

This man was amazing.

I knew this from the minute that Henry Louis Gates told me the story and showed me the picture.

I knew that this was the -- an important piece of the puzzle I needed to understand my stake in the country.

JEFFREY BROWN: Your own stake.

ANNA DEAVERE SMITH: My own stake in the country.

So these are some of the kinds of things... JEFFREY BROWN: Making sense of her country has been Smith's long-running project.

ANNA DEAVERE SMITH: ... that qualify slavery as the most outrageous crime.

JEFFREY BROWN: But typically through the words and voices of others, as she's helped pioneer a style of documentary theater that has explored traumas and social issues in American life in works such as 1992's "Fires in the Mirror."

ANNA DEAVERE SMITH: And people would say to me, gee, I like your new haircut.

And I'd have to say, it's not mine.

Yes, when I first heard about this case... JEFFREY BROWN: And "Twilight: Los Angeles" the next year.

Both focused on riots in major American cities, for which she interviewed real protagonists and then portrayed them, taking on a wide variety of personas in a one-woman show.

ANNA DEAVERE SMITH: And if I had to choose between argue with people by my hairstyle or giving James Brown that one tribute he asked... The work that I got known for was work about looking at moments of disarray.

And when you look at those kind of issues, number one, nobody agrees, and I love that.

That's dramatic.

Nobody agrees.

And, two, there's no one answer.

So this work was about trying to make sense by putting the pieces together.

JEFFREY BROWN: In 2015, we watched her in action as she researched and talked to residents of her hometown of Baltimore for a show titled "Notes From the Field"... ANNA DEAVERE SMITH: You put leg shackles on a man who can barely walk?

JEFFREY BROWN: ... about how students of color from poor communities are often funneled into the criminal justice system, known as the school-to-prison pipeline.

ANNA DEAVERE SMITH: I made a decision to go on the road, as I call it, to search for American character.

And so that was going to, in particular, cause me to, well, chase that which I'm not.

JEFFREY BROWN: But why?

Tell me why.

What has been the goal in that?

ANNA DEAVERE SMITH: The goal was to come close to strangers quickly in order to try to touch the American spirit.

I knew -- I felt I had to go outside of my metaphoric home, outside of what I knew to understand a country so vast as ours.

JEFFREY BROWN: In her new play, "Basil Biggs," she's done something different.

We recently joined Smith for a workshop production at Philadelphia's Wilma Theater, a work in progress put on as part of a citywide arts festival called What Now.

For Smith, what now involves looking hard at what then for the mixed-race son of a slave owner and enslaved woman now living as a freeman with his family and working as a veterinarian.

ACTOR: You rock that baby like (INAUDIBLE) ACTRESS: I swear it can make sense.

ANNA DEAVERE SMITH: I'm trying to figure out who he was because he didn't read or write.

So, given the fact that what I have trained myself to do is to study words and language to find identity, here, I have no words.

JEFFREY BROWN: What she did have, photographs of Basil Biggs and his family, archives describing life in Gettysburg at the time, and a record of another astounding aspect of Biggs' life revealed on "Finding Your Roots" and also portrayed in the play.

After the Battle of Gettysburg, he disinterred the Union dead for reburial in a new cemetery ahead of Abraham Lincoln's famous address delivered on November 19, 1863.

Most important, Smith says, she was able to visit the actual farm and homes where Biggs and his family lived.

ANNA DEAVERE SMITH: So this gave me a sense of place.

And it turned out that the sense of place was as grounding as words had been before.

JEFFREY BROWN: Really?

ANNA DEAVERE SMITH: Yes.

JEFFREY BROWN: So, place meaning what you see, what you smell, what you -- the wind in your... ANNA DEAVERE SMITH: And in my sense of belonging in it, in belonging in the story myself, that the fact that myself belonged -- and I haven't thought about this until talking to you, but that myself belonged in this story, that I could believe myself in this story, because I was in the house and in the barn and on the creek, helped me begin to imagine this man, Basil Biggs.

JEFFREY BROWN: What did it teach you about yourself or what did it -- made you think about yourself today as an American today?

ANNA DEAVERE SMITH: I know why I care.

I know.

And I can't give you the words for it, but in a kind of intuitive way, I know why I care about America, because, for one thing, my great-great-grandfather cared enough about America that he wanted these soldiers to have a decent burial.

JEFFREY BROWN: The play takes its characters and us up to 1872.

The civil war is over, but the struggles continue.

(SINGING) JEFFREY BROWN: Including the new presence of the Ku Klux Klan.

ANNA DEAVERE SMITH: The audience is left with a rebel yell, and I hope they are there for going to think about the work we have to do now before we can sing the songs about everything's going to be all right, because we all know it's not all right.

JEFFREY BROWN: It's an ambiguous ending for Anna Deavere Smith's great-great-grandfather and for the country down to today.

For the "PBS News Hour," I'm Jeffrey Brown at the Wilma Theater in Philadelphia.