Which NFL teams have new head coaches? Jim Harbaugh among 8 coaches.

Macdonald, 37, is the youngest active NFL head coach, succeeding Pete Carroll, who was the oldest head coach at 72 before retiring after last season. Before joining the Seahawks, Macdonald spent nine seasons on John Harbaugh's coaching staff in Baltimore. With the Ravens, he held a variety of positions, from defensive backs coach (2017) to linebackers coach (2018-2020) to defensive coordinator (2023). Macdonald will bring his defensive mindset to Seattle, which allowed 23.6 points per game last season (8th worst in the league).

Brian Callahan, Tennessee Titans

• Earlier: Offensive Coordinator of the Cincinnati Bengals (2019-2023)
• Successful: Mike Vrabel (2018-2023)

Callahan, 40, got his first chance as a head coach after serving as the Bengals' offensive coordinator for five seasons. In his short time in Tennessee, Callahan has built a new offense around quarterback Will Levis that was previously focused on running under Vrabel. Coaching is in Callahan's blood: His father, Bill Callahan, was head coach of the Oakland Raiders (2002-2003). Earlier this year, Bill Callahan left the Cleveland Browns coaching staff to work under his son as offensive line coach in Tennessee.

Dan Quinn, Washington Commander

• Earlier: Dallas Cowboys defensive coordinator (2021–2023)
• Successful: Ron Rivera (2020-2023)

Quinn, 53, is back to being a head coach in the NFL. Quinn was the Falcons' head coach from 2015-2020 and led Atlanta to an appearance in Super Bowl 51 in 2017, where Atlanta blew a 28-3 halftime lead to Tom Brady and the New England Patriots. Quinn found a new home as the Dallas Cowboys' defensive coordinator in 2021 after being fired in Atlanta in 2020. Quinn's defensive unit in Dallas allowed just 18.5 points last season (fifth-best in the league).