Alvarez, 58, will turn over the football program he has so diligently built into national prominence to Bielema, his second-year defensive coordinator, who is more than two decades his younger.
"I felt truly fortunate to have a coach on my staff who will continue the level of success that we've enjoyed," Alvarez said. "Although we've spent just one season together, I couldn't be more convinced that Bret Bielema is the right man to replace me."
The 35-year-old Bielema endeared himself to Alvarez and the Badger players last season, when he helped mold UW's defense into one of the nation's best. Under Bielema's guidance the Badgers took on their new coordinator's personality: aggressive, confident and well-prepared.
"Bret shares many of the same traits that Barry has, that made him such a great football coach," UW chancellor John Wiley said. "He's dynamic, he's personable. He has the confidence and the energy to lead."
"Players will work extra hard for him because he works extra hard for us," senior cornerback Brett Bell said.
Bielema has rocketed up the coaching ladder since finishing his playing career at the University of Iowa in 1992. After playing under legendary coach Hayden Fry, Bielema stayed with the Hawkeyes for nine years as an assistant to Fry and Kirk Ferentz, first as an undergraduate student assistant, then as a graduate assistant, before serving as linebackers coach for six seasons (1996-2001).
Partly for that reason, Alvarez, who was 42 when he took over the UW program, dismissed concerns regarding the next Badger coach's youth.
"I know how difficult and how tough Hayden Fry is," said Alvarez, who was an assistant under Fry for eight years. "To make him a graduate assistant and then to make him a full-time coach I think sent a strong message to me and then the fact Kirk held him over."
Prior to becoming UW's defensive coordinator and co-linebackers coach, Bielema spent the 2002 and 2003 seasons as the co-defensive coordinator under Bill Snyder at Kansas State.
"I think [Bielema's] capabilities far exceed what some people may perceive to be his youthfulness," Snyder said. "He's well-organized and I think he has a tremendous working knowledge of the game, and not just on defense, but offensively and with special teams."
Bielema said that seeing firsthand how Ferentz took over for Fry will help him as he prepares to take over for Alvarez.
"[Ferentz] replaced a legend in Hayden Fry and the transition I experienced my first three years with him are going to be very beneficial in the transition that I now have to face," Bielema said.
Originally a walk-on at Iowa, Bielema was a member of the Hawkeyes' Big Ten title winning team in 1990 and a starting defensive lineman on the '91 team that finished No. 5 in the nation. He was a team captain as a senior in '92.
"I first experienced Wisconsin from the wrong side," said Bielema, who has a tattoo of a Tiger Hawk on his leg. "I came in as a visitor wearing the wrong color….
"I'll have it be known that I never lost to (Alvarez) as a player," Bielema added with a smile. "But as a coach I did and maybe that was because I was coaching."