He did an absolutely remarkable job as the Indianapolis Colts' interim head coach in 2012, playing a large part in leading the previously 2-14 club to an 11-5 record and a berth in the postseason.
After things went stale with Ken Whisenhunt, it was time for the Cardinals to head in a different direction.
With Arians at the helm, expect these four new developments in Arizona.
There's a chance, albeit a small one, that Bruce Arians sticks with Kevin Kolb as his quarterback in 2013.
Frankly, he shouldn't.
While Kolb has the arm strength to operate Arians' vertical passing system, the former Philadelphia Eagles signal-caller hasn't been able to stay healthy or prove himself over the long haul as a starter.
With that, expect Arians to find his own big-armed quarterback who has the ability to frequently threaten a defense down the field.
N.C. State's Mike Glennon or Arkansas' Tyler Wilson instantly come to mind as quarterbacks who could be targeted by Arians and theoretically fit his system.
Ready for this stat?
(Disclaimer: You're not)
The Arizona Cardinals have allowed 162 sacks since the beginning of the 2010 season.
Sure, some of that has been the direct result of shaky quarterback play, but come on, 162 sacks?
Some will say left tackle Levi Brown played better at the end of the 2011 campaign and Bobby Massie improved during the latter stages of 2012, but there's no way Arizona should neglect to upgrade its offensive front in the offseason.
Good edge-protectors are vital in Arians' system, so don't be surprised if the Cardinals look to add more depth at their tackle position in the draft or free agency.
Remember when Larry Fitzgerald was an elite deep threat?
When he made cornerbacks look like JV players on jump balls?
That was a fun time, wasn't it?
In 2012, the supremely gifted wideout averaged a pedestrian 11.2 yards per catch.
Though Fitzgerald isn't a true burner, his ball skills are arguably the best in football, and he can undoubtedly still make an impact down the field.
In Arians' system, expect that to happen.
Regardless of who's throwing him the football, Fitzgerald should be used as the primary big-play wideout.
The Arizona Cardinals carried the ball 352 times in 2012, the fewest in the NFL.
In fact, under Ken Whisenhunt, the Cardinals finished with the fewest amount of carries in four of the last five seasons.
Much of the running game abandonment was due to continually falling behind, but with Arians, the Cardinals will run the football much more frequently.
During his time with the Pittsburgh Steelers, Arians never implemented a necessarily "run-heavy" attack, but his teams consistently ran the ball over 420 times a season.
The Colts ran the ball 440 times in 2012.