Joachim Heinlein was born in Cologne in 1951 and lives there. He studied education, worked at the University of Cologne and was an official at the Paritätischer Wohlfahrtsverband (Parity Welfare Association) for many years. This was followed by five years as managing director of workshops for people with disabilities. From 1999 to 2017 he was Commercial Director and later also Chairman of the Board of LVR-Klinikum Düsseldorf - Kliniken der Heinrich-Heine-Universität Düsseldorf.

Politically, Joachim Heinlein comes from the initiative movement of the 70s. From 1984 to 1999, he was a member of the Green parliamentary group in the Rhineland Regional Council (LVR) with a focus on social issues and health. Until spring 2020, he was a member of the board of the Green local association of Cologne-Nippes in various functions for 20 years. Since the local elections in 2014, he has been a member of the Green councillor group in Cologne and a member of the supervisory board of two municipal hospital companies. He is a board member of Köln-Archiv e.V., a large archive of regional social movements, and of the Stiftung Psychiatrische Hilfsgemeinschaft Rheinland (Psychiatric Support Group Foundation).

Since 2013, Joachim Heinlein has been a member of the board of the Heinrich Böll Foundation NRW, and between May 2015 and 2023  was a member of the general assembly of the Heinrich Böll Foundation at the federal level.