He has held various positions in the administration and the Government including the top post of the country as the Prime Minister of Papua New Guinea from July 1999 to August 2002.  

Other positions held in Government include: 

• Leader of Opposition, Papua New Guinea from August 2002- May 2004.

• Minister for Fisheries, Government of Papua New Guinea – From April 1998 to June 1999.

• Minister for Planning and Implementation, Government of Papua New Guinea – From December 1997 to April 1998.

• Chairman - NCDC Board - June 2004 to August 2006.

• Member for Port Moresby North-West, Papua New Guinea National Parliament - Since July 1997. 

Sir Mekere has also held numerous positions in the public sector: 

• Governor, Bank of Papua New Guinea - 1993 – 1994.

• Managing Director, Papua New Guinea Banking Corporation - 1983 -1992

• Secretary, Department of Finance, Government of Papua New Guinea - 1973 – 1982. 

Sir Mekere represented the Government of Papua New Guinea as Alternate Governor on the Board of Governors of the Asian Development Bank and the World Bank and its affiliated bodies and the International Monetary Fund in his capacity as Secretary for Finance and Governor of BPNG respectively. 

Sir Mekere served the following Boards prior to entering politics: 

Chairman, Bank of Papua New Guinea (1993-1994), Chairman, National Airline Commission (1992-1994), Commissioner, National Airline Commission 1973 - 1994), Papua New Guinea Banking Corporation (1973 -1982 and 1983 - 1992), Chairman, Nambawan Finance Limited (1983-1992), Highlands Gold Limited (1989 -1993), Mount Isa Mines (PNG) Limited (1989-1993), Barracuda Pty Limited (1989-1993), Angco Limited (1983-1993; 1994 - 1998), James Barnes PNG Pty Ltd (1984 - 1993), P.N.G. Associated Industries Ltd (1983 -1993), Member of Advisory Board for South Pacific Project Facility, International Finance Corporation (1992-1995).  

He was also a member of the boards of the Papua New Guinea Development Bank, Investment Corporation of Papua New Guinea, PNG Electricity Commission, Post and Telecommunication Corporation, Bougainville Copper Limited, Ok Tedi Mining Ltd and Chairman of National Provident Fund and Public Officers Superannuation Fund. 

Sir Mekere has been awarded with the following recognitions:

• Doctorate of Technology (Honorary) by University of Technology, Papua New Guinea - 1987

• Knight Bachelor - 1990

• Privy Councillor – 2001

•  Doctorate of Economics (Honorary), University of Papua New Guinea – 2001.