Take all the elements that make for good television, do the exact opposite, and you might have something like Mister Rogers Neighborhood, says a producer of the beloved series in this new trailer for the upcoming doc Won’t You Be My Neighbor?

And yet, the series, with its low production values and unlikely star, not only worked, but became iconic, an exemplar of children’s TV programming. How?

“He was saying something really important,” says producer Margy Whitmer about Fred Rogers, the series’ low-key, soft-spoken host.

The Focus Features documentary, directed by Academy Award-winning filmmaker Morgan Neville (20 Feet from Stardom), is described by Focus as an intimate look at America’s favorite neighbor: Mister Fred Rogers. The logline reads: A portrait of a man whom we all think we know, this emotional and moving film takes us beyond the zip-up cardigans and the land of make-believe, and into the heart of a creative genius who inspired generations of children with compassion and limitless imagination.

In the trailer, which includes behind-the-scenes footage as the Mister Rogers crew prepares the show’s set (hanging sweaters in a closet, placing Trolly on its tracks), Fred Rogers sums up the guiding principle and the key to that unlikely success.

“Love,” Rogers says, “is at the root of everything – all learning, all parenting, all relationships, love. Or the lack of it. And what we see and hear on the screen is part of who we become.”

Focus Features will release Won’t You Be My Neighbor? in select theaters on June 8. Take a look at the trailer above.