In July 2016, Purcell qualified for and won the Gimcheon Challenger in South Korea against fellow Australian Andrew Whittington.
The duo lost in the opening round to Spanish pairing Guillermo García López and Pablo Carreño Busta.
Purcell commenced the 2021 season at the 2021 Great Ocean Road Open, where he defeated Norbert Gombos for his first ATP main draw win.
Purcell also replaced Alex de Minaur after he tested positive for COVID-19 in the doubles event,[8] where he partnered John Peers but lost in the first round.
[10] He reached the quarterfinals in doubles at the 2021 US Open partnering Matthew Ebden where they lost to 4th seeds and eventual champions Joe Salisbury and Rajeev Ram.
On 20 September 2021, and following a quarterfinal result at Cary Challenger, Purcell achieved a career high singles ranking of World No.
In January 2022, Purcell made his debut representing Australia at the 2022 ATP Cup, losing to Jannik Sinner in the round robin stage.
[16] Together with Thanasi Kokkinakis and Nick Kyrgios, Ebden and Purcell made it the most Australians to reach this stage of the men's doubles tournament in 29 years, since 1993, and the first time since 1985 that two all-Australian pairings contested the semifinals.
Purcell and Ebden faced Kokkinakis and Kyrgios in the final, the first in men's doubles at the Australian Open to feature two all-Australian teams since 1980,[18] where they ultimately lost in straight sets.
[22] They went on to win their maiden Grand Slam title as a team defeating second seeded pair of Nikola Mektic and Mate Pavic in another more than four hours, five set classic with a super tiebreak.
[24] At the same tournament he reached the quarterfinals partnering Tim van Rijthoven where they lost to eventual champions William Blumberg and Steve Johnson.
At the 2022 Los Cabos Open he qualified for the main draw and defeated Henri Laaksonen before losing to 6th seed Brandon Nakashima.
Despite a successful 2022 doubles campaign, which included two Grand Slam finals and a title, Purcell decided to split from partner Matthew Ebden for the 2023 season, citing a desire to focus on his singles career.
[25] Purcell qualified for the second time at the 2023 Australian Open in singles,[26] but was eliminated in the first round of the main draw after a four set loss against Emil Ruusuvuori.
Purcell partnered fellow Australian Jordan Thompson in the doubles event, but was eliminated in the second round by eventual finalists Hugo Nys and Jan Zielinski.
[34] In May, Purcell reached his sixth Challenger of the season at the 2023 Busan Open in South Korea, where he lost to compatriot seed Aleksandar Vukic after retirement due to right ankle injury.
[41] Purcell started his year at the Brisbane International, where he drew top seed Holger Rune and lost in three sets.
[43][44] In April, as defending champions,[45] the pair Purcell and Thompson won their fourth title as a team at the 2024 U.S. Men's Clay Court Championships.
They were defeated in the final by first time Major champions Henry Patten and Harri Heliovaara in a three-setter with three tiebreaks, after Purcell/Thompson failed to convert three match points in the second set.
[49][50] With Thompson, he reached a second Grand Slam final in doubles for the season at the US Open, defeating American duo and 13th seeds Nathaniel Lammons and Jackson Withrow.
[51] They defeated tenth seeds Kevin Krawietz and Tim Pütz lifting their first Grand Slam trophy as a team, and the first at this level for Thompson and second for Purcell.
[52][53] On 23 December 2024, it was announced that Purcell had been given a provisional suspension by the International Tennis Integrity Agency effective from 12 December, after he admitted violating Article 2.2 of the Tennis Anti-Doping Program “relating to the use of a Prohibited Method.” Writing on Instagram, Purcell said he had "unknowingly received" an intravenous infusion of vitamins which was above the 100ml limit allowed under World Anti-Doping Agency rules.