In August 2015, Sweeny represented Australia at the ITF World Junior Tennis Finals in Prostějov, Czech Republic.

In January 2021, Sweeny made the third and final round of the 2021 Australian Open – Men's singles qualifying.

[5] Sweeny was awarded a wildcard into the 2021 Great Ocean Road Open, where he made his ATP Tour main draw debut.

[9][10] He made his debut in doubles as a wildcard pair partnering compatriot Li Tu reaching the third round where they lost to second seeds Rajeev Ram/Joe Salisbury.

[13] Only main-draw results in ATP Tour, Grand Slam tournaments, Davis Cup and Olympic Games are included in win–loss records.