Pittsburgh's Mike Tomlin is the longest-serving NFL head coach having been appointed in 2007, the year before John Harbaugh took charge at Baltimore
The Baltimore Ravens have ended John Harbaugh's 18-year spell as head coach after the team's failure to reach the NFL play-offs.
The 63-year-old led the Ravens to victory in the 2013 Super Bowl and was the second longest-serving head coach in the NFL.
Harbaugh is the fourth head coach to be sacked since the end of the NFL's regular season on Sunday, with three being dismissed on 'Black Monday'.
The Ravens lost to divisional rivals Pittsburgh in an AFC North title decider on Sunday, with Tyler Loop missing a last-gasp field goal to allow the Steelers to win 26-24 and clinch the final play-off spot.
