[5] After joining the Foreign Service in 1973, Hacker held overseas assignments at Embassy Stockholm, Sofia, Nicosia, Manila and Helsinki.
[6] From January 4, 1993, he served as the embassy's first chief of mission (Chargés d'affaires ad interim) until July 7,[7]: 88 [3] when Eleanor Sutter assumed charge of the post.
[6] He had once worked for the Office of High Representative for Bosnia and Herzegovina (OHR) under Carl Bildt (later Prime Minister of Sweden) after the end of the Bosnian War, and was stationed at Tuzla.
[6] After his retirement, he has worked as translator and editor from Finnish, Swedish, Czech, Slovak, Polish, and Russian.
He also taught a course on diplomacy in 1994 at the Florida International University (FIU) in Miami and also one course on the same subject in 2003 at the Kyiv Mohyla Academy [College].