Co-founder Mazingira Institute, which has been engaged with urban agricultural research and development in Nairobi, Kenya since the 1980s.
Currently, the Institute hosts the Nairobi and Environs Food Security, Agriculture and Livestock Forum (NEFSALF). In 2002-2005 she was African Regional Coordinator for Urban Harvest, a programme of the Consultative Group on International Agricultural Research (CGIAR). From 2006-2009 Dr Lee-Smith was Visiting Professor in Public Health at the University of Toronto where she taught and edited two books, Healthy City Harvests (CIP-IDRC 2008) and African Urban Harvest (Springer NY-IDRC 2010). She is now based at Mazingira Institute in Nairobi.