After a short time as a Preacher, he returned to the Comenius Faculty in Prague, where he habilitated and worked as a lecturer.

Lochman has worked on ecumenical bodies for decades, particularly at the World Council of Churches.

He also worked for the World Alliance of Reformed Churches: from 1970 to 1982 as chairman of the theological department.

Jan Milíč Lochman was one of the co-founders of the Christian Peace Conference.

There he headed the working group "Cold War" together with the German federal Wolfgang Schweitzer and the Hungarian M. Pálfy.