Lowry, the 2019 Open champion, was chasing his first title since September 2022 – but the 36-year-old was unable to sustain his bid after ending each of the first three days at the top of the leaderboard.
He made consecutive birdies on the 15th and 16th holes to make even par and end the weekend on nine under in third place.
Scheffler, champion in 2022 by a single stroke, carded six birdies – including four on the back nine – to seal a dominant victory with his best score over the four days.
It is his seventh PGA Tour title, almost a year to the day since he lost tasted victory at the 2023 Players Championship.
Clark, who began the day one shot behind the leaders, carded a two-under 70 to finish runner-up.
Behind Lowry, Americans Russell Henley and Will Zalatoris both finished on seven under in a tie for fourth place
Northern Ireland’s 2018 winner Rory McIlroy, runner-up last year, shot 76 on Sunday to finish one under par and ended up tied for 21st.