Harris's first appearance in a professional tournament was at the Australia F7 in September 2011, where he made the quarterfinal before losing to Alex Bolt.

Harris lost in round 1 of the 2012 Australian Open qualification to Denys Molchanov, before competing in three Future tournaments in Australia.

[1] Harris successfully returned to competition in May 2013, where he made the final of the Thailand F2, losing to Saketh Myneni of India.

The following week, he made the semifinal of the Thailand F3, losing to fellow Australian Adam Feeney in straight sets.

Throughout June and July, Harris competed in Futures throughout Europe, his best performance being a quarterfinal in Belgium F4, before winning his first title in October in Texas at the USA F27 against Dennis Nevolo.

Harris spend the 2018 year on the ITF Futures and ATP Challenger Circuits across Australia and United States of America.

Harris was awarded a wildcard into the 2020 Australian Open, where he lost in straight sets to 8th seed Matteo Berrettini.

Harris commenced 2021 at the 2021 Murray River Open, where he recorded his first ATP main draw win against Taro Daniel.