"The day I left to take the Philadelphia job I told several people in this building this: I will get an opportunity to come back here," Rivera said.
Rivera had been an quality control assistant on defense with the Bears in 1997-98 during the Dave Wannstedt era.
"It all started here," Rivera said. "I started at the bottom. I came in as a volunteer assistant coach, didn't get paid for a while (1997). Then Michael McCaskey gave me the opportunity and offered me the contract to stay as a quality control coach.
"I did that for two years. It's a lousy job, it's a lot of hard work and it doesn't pay a lot. But in the same sense it also shows that I really wanted to be involved in pro football as a coach and I was willing to make that sacrifice."
Rivera's five years in Philadelphia included aiding the development of Jeremiah Trotter, a two-time Pro Bowl player who has since gone to the Washington Redskins in free agency. His linebackers averaged 129 tackles per man over the five years.
Rivera, 42, had interviewed with the New York Jets but did not receive an offer because coach Herman Edwards planned one more interview.
Smith has three years of defensive coordinator experience and Rivera none, but he Bears' new head coach promised to be more overseer than a hands-on presence.
"I won't be calling the defenses, believe me," Smith said. "Ron is ready to call the defenses. We will have a plan in place. I feel very confident with him leading our defense."
Smith got to know Rivera over the years at the NFL combine and Senior Bowl.
"I've always liked how he coaches and the product he put out on the field," Smith said. Bringing back a former Bears was considered significant by Smith on the day he signed as Bears head coach.
"I think it's great to bring back a former Bear whose had a great career here," Smith said. "I just think all of the things pointed in his direction.
"Ron and I have similar beliefs in how we coach guys and what goals we're trying to achieve. Everything kind of pointed toward him."
While Smith believes they think alike, Rivera came from a different defensive philosophy. He played under blitzing wizard Buddy Ryan in the "46" defense and coached under Jimmy Johnson in Philadelphia. Smith, meanwhile, has been involved with the famed "cover-2" scheme which emphasizes coverage and a four-man pass rush.
Rivera and Smith described the new defense as an attempt to meld the two philosophies.
"I intend to learn from coach Smith," Rivera said. "I think with his record, with what he accomplished down in St. Louis with that defense, I'd be crazy not to. My ego is not so large that I'm not open to suggestions. I'm most certainly not an egomaniac when it comes to whose defense I'm going to use."
It definitely is a defense which will include some of Ryan's fabled scheme, made famous during the Bears' 18-1 run to the Lombardi Trophy after the 1985 season.
"There are some things that Buddy has done, that some other people in this league have done," he said. "In fact Lovie, used some of that stuff down in St. Louis. We used some of it in Philadelphia. There most certainly is a place for some of the old style `46' defense."
Rivera cherishes the opportunity to provide young players with a knowledge of more than just some old Bear schemes. He thinks he can teach some Bears history to them.
"Young football players need people to remind them on occasion just how special it is to be a Chicago Bear," he said. "That's something I will try to do."
Smith now has both coordinator positions filled. Former Chiefs quarterbacks coach Terry Shea took the offensive coordinator spot Thursday. Pete Hoener has signed as offensive line coach and Bob Babich as linebackers coach.