Seth Aaron also filled in for Tim Gunn as the head "casting judge" on Season 9 of Project Runway. Continuing his commitment to a sustainable future, Seth Aaron's designs feature organic fabrics and those made from recyclable plastic bottles. His 2010 Portland Fashion Week collection was sponsored and inspired by Solar World, a manufacturer of solar panels in Oregon, Henderson's home state.
Henderson's show at Portland Fashion Week in October 2011 also featured sustainable fabrics. and he's collaborating with the New Hampshire-based Earthtec clothing company to create a sustainable line of clothing to be sold by an "as yet unnamed national retail chain".
In 2013, Henderson became a contestant on Project Runway: All Stars (season 3).
In 2014, Henderson was announced the winner of Project Runway: All Stars; he is the first to win both Project Runway and Project Runway: All Stars. As part of his prize package, Henderson launched a collection on QVC later that year.
He currently lives in Vancouver, Washington, with his wife, Tina, and two children, Aaron and Megan.