He was the Labor member for the South Australian House of Assembly seat of Playford from the 1997 election until his retirement in 2018.

Prior to his election into politics, Snelling was an electoral officer, and a staffer in the Shop, Distributive and Allied Employees Association (SDA).

[7] A ReachTEL poll conducted on 2 March 2017 of 606 voters in post-redistribution Florey indicated a 33.4 percent primary vote for Bedford running as an independent which would likely see Snelling defeated after preferences.

[9] After the 2010 election, Snelling was appointed as the Minister for Employment, Training and Further Education, Science, Information Economy, Veterans Affairs and Road Safety.

[10] Following the parliamentary resignation of Kevin Foley, Snelling was sworn in as the Treasurer of South Australia on 8 February 2011.