Leonard is a graduate of Bandung Institute of Technology (ITB) as a Bachelor of Petroleum Engineering in 1994. However, he never worked for the petroleum industry. Instead, he dedicated his university years in the student political movement and also became passionate with the environmental movement.

After graduating from ITB, Leonard worked for Yayasan Pelangi, a national environmental NGO based in Jakarta, and became the manager of Energy Program in Pelangi from 1994 to 1997. During this period, Leo was also involved in the Indonesia Anti Nuclear Society (MANI), the Indonesia-Climate Action Network (I-CAN), as well as the National Mining Advocacy Network (JATAM). Leonard’s first involvement with Greenpeace was in 1996 when he collaborated with Greenpeace on a study of the potential spread of radioactive impacts of the proposed Muria Nuclear Power Plant, in Java. Since then, Leonard has gone through a diverse work profile that includes working for Oxfam Australia (PIKUL) where he worked on a range of issues: civil and political rights, social and economic rights, indigenous people’s rights to natural resources, mining, food security, disaster preparedness and response, displacement and refugees, conflict and peace building.

In 2006, Leonard was one of the founding members of Greenpeace Indonesia and has been one of the national board members since then. He joined Greenpeace Southeast Asia, as Country Director for Greenpeace Indonesia since July 2016 until now. Leonard also serves as the Chairman of Supervisory Board of Transparency International Indonesia (TI-I), on a voluntary basis. He has been involved as member of the Supervisory Board and Governing Board of TI-I since 2009.