As a primary and secondary school pupil in St. Märgen , Rießle took part very successfully in the school competitions for young people trained for the Olympics . In 2004 he became the German vice-student master. In 2005 he made his international debut in FIS races and in the Alpine Cup. From 2008 he started in the B World Cup. On January 4th, 2009 he made his debut in the Nordic Combined World Cup . At the Junior World Championship in 2009 in Štrbské Pleso he won the individual over 5 km and the bronze medal with the team. A year later he won the gold medal with the team at the Junior World Championships in Hinterzarten . After he had won World Cup points for the first time in the 2009/10 season , he finished the season in 60th place overall.
He took his first podium in the World Cup on January 13, 2012 with 3rd place in Chaux-Neuve , where he was third again a day later, just 0.1 seconds behind Alessandro Pittin . Already on January 7th he had finished 2nd with the German relay in Oberstdorf , only 0.1 seconds behind Norway. On December 15, 2012, after a weak start to the 2012/13 season, he surprisingly reached the podium in Ramsau in third place and, together with Tino Edelmann , took second place in the team sprint on March 9, 2013 in Lahti .
On January 12, 2014, Rießle won a World Cup competition for the first time when he and Tino Edelmann won the team sprint in Chaux-Neuve. Two weeks later he won the team competition in Oberstdorf with the German team. At the Olympic Games in Sochi , he unexpectedly won the bronze medal on the large hill behind the two Norwegians Jørgen Graabak and Magnus Moan . In the competition on the normal hill he had previously taken eighth place. In the team competition on February 20, 2014, he won the silver medal as the final runner. For this, like the other three, he was awarded the Silver Laurel Leaf on May 8, 2014 by Federal President Joachim Gauck .
At the beginning of the 2014/15 World Cup season , Rießle achieved his best individual results to date with two second places in Lillehammer on December 6th and 7th, 2014, with which he also took the lead in the overall World Cup, which he held until January 17th. At the 2015 World Championships in Falun , he won the team competition together with Tino Edelmann , Eric Frenzel and Johannes Rydzek , winning the first German gold medal in 28 years.
On December 5, 2015, Riessle won his first World Cup competition in Lillehammer . After two more victories, he finished third in the final ranking of the World Cup . In the 2016/17 World Cup , he won two individual competitions in Lahti and Chaux-Neuve and with the team in Lillehammer. He finished fourth in the overall standings.
At the 2018 Winter Olympics , he won silver in the triple success of the German combined athletes on the large hill and gold in the team competition.