Complex sentence: After retiring as a player in 2003, he became manager of St. Mirren, a position he held until May 2010, taking St. Mirren from the First Division to the SPL and the 2010 Scottish League Cup Final.
Split into simpler sentences: After retiring as a player in 2003, he became manager of St. Mirren, a position he held until May 2010. MacPherson took St. Mirren from the First Division to the SPL and the 2010 Scottish League Cup Final.