[8] McLennan created the Living Building Challenge, a sustainable design performance standard, while he was a principal with BNIM Architects.
He transferred the intellectual property for the Challenge to Cascadia Green Building Council when he became that organization's CEO in 2006, and formally launched the program in November of that year.
[11] McLennan was named an Ashoka Fellow in 2012 for "creating incentives and new practices so that the built environment improves health, well-being while increasing our access to a diverse and productive natural world.
"[12] In 2012, he was also appointed to join Deepak Chopra, Dick Gephardt, Mel Matinez and Terry McAuliffe on the advisory board of Delos,[13] a wellness real estate development firm founded by Paul Scialla.
[15] McLennan's residence, Heron Hall, was named “home of the month worldwide" by Architectural Record in 2017.