From 2009–2011, he was a Fellow at the Simon Fraser University Centre for Dialogue, researching, teaching and organizing public events around the theme Planning Cities as if Food Matters.
During his time on Vancouver City Council, Ladner was a sustainability and liveability advocate on issues such as transportation, green buildings, energy use, and waste reduction.
He also served on the boards of the Institute for Media, Policy and Civil Society, Leadership Vancouver, the International Centre for Sustainable Cities, the University of British Columbia Alumni Association, New Media BC, the International Association of Area Business Publications, the Fraser Basin Council and the Forum for Women Entrepreneurs.
Ladner is a long-time environmentalist, healthy living enthusiast, and advocate of the smart city concept of using technology to make government more efficient and effective.
He is a former age-group record holder in the North Shore Knee-knackering Trail run, a 50-km ultramarathon from Horseshoe Bay to Deep Cove.
On April 3, 2009, Peter Ladner's sister, Wendy Ladner-Beaudry, was found dead in Pacific Spirit Park, "the victim of an apparent random attack.
"[3] John Furlong (VANOC CEO) had become a close friend to Wendy and reserved a spot in the 2010 Olympics Torch Relay for the Ladner-Beaudry family.