J.R. Grubbs is a supervising sound editor whose work spans both film and television, with a career rooted at Skywalker Sound. He began his career in the early 1990s, initially credited in roles such as assistant sound editor or sound assistant on films including Wild at Heart (1990), Rush (1991), Miracle on 34th Street (1994), Toy Story (1995), Terminator 2: Judgment Day (1991), and others. Over the years, he gained experience and rose through the ranks, later taking on the role of supervising sound editor on films such as Coco (2017) and Dolittle (2020), among many others.

Grubbs contributed significantly as a sound effects editor (and occasionally supervising sound editor) on a wide array of high-profile feature films—including Minority Report (2002), Iron Man (2008), Shang-Chi and the Legend of the Ten Rings (2021), Captain Marvel (2019), Doctor Strange (2016), The Avengers (2012), Captain America: The Winter Soldier(2014), Guardians of the Galaxy Vol. 2 (2017), and The Marvels (2023)—as well as celebrated television series such as The Mandalorian (2019–present) and Andor (2022–present). In more recent years, he held the supervising sound editor title on Shang-Chi and the Legend of the Ten Rings (2021) and Dolittle (2020).

Throughout his career, Grubbs has earned multiple professional awards and nominations. Notably, he has won several Golden Reel Awards—presented by the Motion Picture Sound Editors—for his exceptional work. His wins include awards for The Mandalorian (Season 2, 2020) in the category of Outstanding Achievement in Sound Editing – Episodic Short Form – Effects/Foley (for “The Jedi”), Coco (2017) for Outstanding Achievement in Sound Editing – Feature Animation, Wreck-It Ralph (2012), and Up (2009). In total, he has received four wins and twenty nominations, including nominations for Primetime Emmy Awards.

Beyond his wins, Grubbs has been nominated multiple times for Golden Reel Awards for his sound effects editing work on major Marvel Cinematic Universe films including Iron Man (2008), Iron Man 2 (2010), The Avengers (2012), Captain America: The Winter Soldier (2014), Doctor Strange (2016), and Captain America: Civil War (2016).