"I've worked with Kirby and Bo and know the qualities they possess," Saban said in a statement. "They both have coached at successful major college programs, allowing them to make a smooth transition to the NFL. They are excellent teachers and will be positive additions to our staff."
Smart comes to the Dolphins after one season as running backs coach at the University of Georgia, his alma mater. As defensive backs coach at LSU in 2004, Smart worked with, among others, Dolphins cornerback Travis Daniels.
Davis, meanwhile, spent the last four seasons at LSU, where he spent three years as a defensive lineman from 1990-92.
For those keeping score, that's four new assistants hired this offseason, the other two being offensive coordinator Mike Mularkey and assistant to the head coach Dom Capers.
The Dolphins have lost four assistants from last year's staff: Scott Linehan, Will Muschamp, Richard Smith and Judd Garrett.