Previously, he worked as associate professor at Dillard University (USA) and before that as a research assistant at the Centre for Policy Analysis (Ghana).
[6] He served in that role until 6 January 2009 when the New Patriotic Party handed government over to the opposition National Democratic Congress, which had won the 2008 general election.
[3][7] In February 2017, Osei was sworn in as Minister of Monitoring and Evaluation after being nominated by President Nana Akufo-Addo and going through the vetting process in the parliament of Ghana.
[10] In May 2017, President Nana Akufo-Addo named Anthony Akoto Osei as one of 19 ministers who would form his cabinet.
The names of the 19 ministers were submitted to the Parliament of Ghana and announced by the Speaker of the House, Right Honourable Professor Aaron Mike Oquaye.
As a cabinet minister, Osei was part of the president’s inner circle and assisted in key decision-making in Ghana.
[14][15] He was elected over Salu Ibrahim of the National Democratic Congress, Andrews K Asamoah-Akoto of the Convention People's Party and Amediku Dominic D Quarshie an independent candidate.
[18][19] He was elected over Swallah Ali of the People's National Convention, Dominic Kwabena Anomah of the National Democratic Congress, Issah Abdul Salam of the Convention People's Party and Mohammed Rabui Umar of the Reformed Patriotic Democrats.