Turned professional in 2012, shortly after making the winning putt for The University of Texas at the NCAA Championships played at Riviera CC.

The three time All-American was a top 10 ranked amateur in the world when turning professional. He quickly gained status on the European Challenge and Sunshine Tour's, winning twice on the Challenge Tour (Karnten Open & Rolex Trophy) before graduating to the DP World Tour in 2017.

Frittelli claimed his first European Tour victory in 2017 at the Lyoness Open powered by ORGANIC+, after losing in a playoff weeks earlier at the Volvo China Open.

Shortly after celebrating being named 2017 Graduate of the Year, he notched another win at the AfrAsia Bank Mauritius Open. After joining the PGA TOUR in 2018 he won the John Deere Classic his rookie season, and managed to make the FedEx Cup Finals four years in a row.

In 2020 Frittelli finished fifth at the Masters Tournament, and the next year finished fifth at the Open Championship.

Upon his return to the DP World Tour in 2024 he won his third title at the Bahrain Championship presented by Bapco Energies.