[6] Ofner made his ATP main draw debut at the 2017 Wimbledon Championships after going through qualifying, defeating Kimmer Coppejans, Miljan Zekić and Jay Clarke.

[1][7] In August, Ofner caused another surprise in front of his home crowd at the 2017 Generali Open Kitzbühel by defeating first seed Pablo Cuevas as a wildcard in the second round.

[10] In the first three months of the season Ofner reached three Challenger Tour finals in Tenerife,[11][2] Antalya[12] and in Zadar.

118, he qualified for the main draw of the 2023 French Open for a second consecutive year and defeated Maxime Cressy for his first win at this Major.

[15][16] He went one step further and defeated Fabio Fognini to reach the fourth round of a Major for the first time in his career.

[17] He further reached the top 70 following a Challenger final showing at the 2023 Ilkley Trophy where he lost to Jason Kubler.

At the 2023 Astana Open, he reached the semifinals defeating third seed Alexander Bublik and this time compatriot Dominic Thiem.

[21] Ofner reached the semifinals in Hong Kong defeating Mackenzie McDonald, fifth seed Jan-Lennard Struff and Roberto Bautista Agut.

[23] He made his debut at the 2024 Australian Open where he lost to Thanasi Kokkinakis in a tight five setter with a fifth set tiebreak.