Oliver Marach, between 2009 and the beginning of 2011, played regularly with the Polish Lukasz Kubot with whom he won five ATP titles as well as nine other finals. The couple also participated in the ATP Finals for two consecutive years, in 2009 and 2010, without however being able to pass the round robin.
He later won two titles with his compatriot Peya between 2011 and 2012, two finals, one of which he won, with the Pakistani Qureshi in 2015, and one title each with the Spanish Santiago Ventura, with the Argentine Leonardo Mayer and with the Romanian Mergea.
In 2016 he began a fruitful collaboration with the French Fabrice Martin with whom he won two titles and played three other finals, including the first of his career on grass. From 2017 to 2019 he teamed up with Mate Pavic with whom he won six titles out of thirteen finals and qualified for the Finals for two consecutive years. He won the title at the 2018 Australian Open and also reached the final at 2017 Wimbledon and 2018 Roland Garros.
Marach has competed in nine editions of the Davis Cup since 2003. For Austria he recorded four wins and one loss in singles between 2003 and 2015; in doubles he has a balance of seven wins and six defeats, gained between 2011 and 2021.