Muir was also a member of the Indianapolis Colts, St. Louis Rams, New York Jets, Kansas City Chiefs, Houston Texans and Oakland Raiders.

In July 2024, Muir and his wife were arrested on criminal charges related to the abuse of their son.

He earned All-State honors after finishing his senior season with 96 tackles, including 13.5 sacks.

He also left Kent State ranked third in school history in career sacks (14.5) and seventh in tackles-for-losses (35).

In 2005 as a junior, he started 11 games and earned Second-team All-MAC honors, he recorded 52 tackles, 8.5 for losses, and three sacks.

[4] Muir joined the St. Louis Rams on July 31, 2011, by signing a one-year $1.85 million contract.

[13] Muir was invited to join the Tennessee-based Black Hebrew Israelite group that preaches Biblical literalism[14] by former Packers teammate Kabeer Gbaja-Biamila.

[15] Muir was named a person of interest by Indiana State Police in the disappearance of his 14-year-old son Bryson on June 27, 2024.

Bryson, who went missing on June 16, 2024, was found on July 3 safe during an Indiana State Police raid on the Muirs' Logansport property and placed in child services.

[16][17][18] The couple were denied bond as they were deemed flight risks,[19] and their trial was scheduled for March 10, 2025.