Riegler joined the youth set-up of SKN St. Pölten from SK Rapid Wien in March 2007,[1] and he advanced quickly through the club's youth system, making his debut in the Austrian Football First League as a stand in for injured first-choice goalkeeper Thomas Vollnhofer in a 1–0 win against SC Austria Lustenau on 15 October 2010.

After missing the start of the following season due to international commitments, Riegler re-established himself as his team's first-choice goalkeeper on his return.

On 23 December 2021, it was announced that Riegler would join SC Rheindorf Altach on a six-month contract, after having played more than 10 seasons and 300 league games for SKN St.

[2] In January 2023, Riegler signed with Austrian Regionalliga East club Kremser SC, after six months as a free agent.

[3] Riegler has represented the Austria under-21s on eight occasions, and he was an unused member of the Austrian squad at the 2011 FIFA Under-20 World Cup.