Born in Sydney, Matt started playing football for Hornsby Heights Hornets before joining Northern Tigers, Gladesville Spirit and Manly United.His next move was into the National Youth League with the Necastle Jets in 2009/10 but it wasn't long until Sim was playing senior football when he returned to Manly United in 2010, spending three seasons with the NPL club, winning the Waratah Cup in 2011 and featuring in the 2013 NPL Team of the Year.
Matt moved to fellow NPL club Sutherland Sharks in 2014 for but didn’t stay for long as he finally made his Hyundai A-League breakthrough, moving to Central Coast Mariners where he played in the AFC Champions League and Hyundai A-League.
Sim developed a reputation as one of the side’s most trusted performers, once coming off the bench to score a record four goals in 19 minutes in the Mariners’ Westfield FFA Cup clash against Palm Beach Sharks in 2014.
A hugely versatile player who can plug any gap on the left side and in midfield, Sim left the Mariners in the 2016 January transfer window and on 1 February 2015 was announced as a Western Sydney Wanderer, making his debut against Brisbane Roar in Round 22.
Matt departed the Wanderers at the conclusion of his contract on Thursday 5 May 2016.