Until 2018, Nelson hosted Animal Planet’s television series, Treehouse Masters.

He lives with his wife, Judy, in Fall City, Washington and has three adult children, all of whom work in the family treehouse-building business.

[6] Nelson owns and operates Nelson Treehouse & Supply in Fall City, WA, 30 miles outside of Seattle and the company is a family affair, with wife Judy, daughter Emily and sons Charlie and Henry, all involved.

[3] The 1994 publication of Treehouses: The Art and Craft of Living Out on a Limb inspired him to write 5 more books on the subject.

[9] In 2016, Nelson collaborated with country music star Zac Brown to build a 1,300 square foot treehouse at Brown's Camp Southern Ground, a non-profit designed to serve children with neuro-developmental disorders as well as children from military families struggling with PTSD.