Pendrith turned professional in late 2014, after the Eisenhower Trophy. In 2015 he played mostly on PGA Tour Canada. He was runner-up three times and finished third in the Order of Merit to earn a place on the Web.com Tour. He finished tied for fourth place in the Club Colombia Championship, his second event on the 2016 Web.com Tour, but this was his only top-10 finish of the season and he missed the cut 14 times.[7]
Pendrith played primarily on the Canadian Tour from 2017 to 2019. He had little success in 2017 and 2018, however in 2019 was runner-up in the Osprey Valley Open, then won the 1932 by Bateman Open and Mackenzie Investments Open to finish second in the Order of Merit and earn a place on the Korn Ferry Tour.[8][5] Playing on the 2020 Korn Ferry Tour, Pendrith was runner-up in three consecutive tournaments in July and runner-up again in the Wichita Open in September. His performances on the Korn Ferry Tour earned him a place at the 2020 U.S. Open where he finished tied for 23rd place after a final round of 70.[9]
Pendrith earned a promotion to the PGA Tour from the Korn Ferry Tour at the conclusion of the 2020–21 season.
In July 2022, Pendrith had his best finish to date on the PGA Tour with a T2 at the 2022 Rocket Mortgage Classic.[10]
In September 2022, Pendrith was selected for the International team in the 2022 Presidents Cup, although he lost all four of the matches he played.[11]
In May 2024, Pendrith won the CJ Cup Byron Nelson for his first PGA Tour win, in his 74th career PGA Tour start.[2][12]