MacPherson has been selected ahead of over 30 original candidates including former Morton manager Allan Moore and ex-Ayr boss Brian Reid, plus one-time Falkirk manager Eddie May.
The 45-year-old former Rangers, Kilmarnock, Dunfermline and St Mirren player was in charge of the Paisley side from December 2003 to May 2010. During his time, his team won the Challenge Cup as well as the First Division and promotion to the SPL.
Saints maintained their status in the top flight during the rest of MacPherson’s stay, which ended just two months after a disappointing Co-operative Insurance Cup Final against a nine- man Rangers side, which the Ibrox side won 1-0.
MacPherson took over at Palmerston from Kenny Brannigan, a former Queen’s Park manager, in June 2011. However, that season was a struggle for the Doonhamers and he left following their relegation to the Second Division the following May.