Born in Westerheim (Württemberg) , Bohnacker was an alpine ski racer at the beginning of his sports career . He took part in FIS races and national championships from January 2006 , but could not achieve any successes worth mentioning. After the 2008/09 season he switched to the freestyle discipline of ski cross. At first it was mainly used in the European Cup. He made his debut in the World Cup on March 14, 2009 in Hasliberg , where he did not get past 78th place.
Bohnacker missed qualifying for the Winter Olympics in the 2009/10 season . On March 12, 2010, he won World Cup points for the first time as tenth in the World Cup race in Grindelwald . In October 2010 he began to study business informatics. Bohnacker achieved his breakthrough to the top in the winter of 2010/11 . After a cautious start to the season, he won the race in Alpe d'Huez on January 12, 2011 . Almost two months later, the second podium followed in Hasliberg. In the 2011/12 season , a third place was his best result, in the 2012/13 season a second place. He achieved two podium places in the 2013/14 season ; there were also six other top 10 placements, which put him in third place in the ski cross discipline. At the 2014 Winter Olympics , he finished in 19th place.
Two podium places and four further top 10 placements meant for Bohnacker seventh place in the ski cross discipline of the World Cup in winter 2014/15 . In the following winter of 2015/16 , he achieved five top 10 placements. Towards the end of the 2016/17 season he again achieved a podium finish with third place in Sunny Valley. In the 2017/2018 season, Bohnacker tore a cruciate ligament in Nakiska and missed participation in the Olympic Games in Pyeongchang. In the 2018/19 season he got back into racing. With four top 10 results he finished 16th in the overall ranking. In the 2019/2020 season he achieved third place in Nakiska and his second World Cup victory in Idre, Sweden. He finished the World Cup season with eighth place in the ski cross discipline.