The 57-year-old Zduriencik, known for his skill in drafting players, replaces Bill Bavasi, who was fired in June, and takes over for interim GM Lee Pelekoudas.
Since Zduriencik arrived in Milwaukee in 1999, the team drafted Prince Fielder, Rickie Weeks, J.J Hardy and 2007 NL Rookie of the Year Ryan Braun -- the young foundation of Milwaukee's playoff team this season.
"Seattle is an outstanding organization with great fans, a great ballpark and an ownership group committed to the goal of bringing a World Series to the Northwest," said Zduriencik, who has spent 25 years in the majors after coaching football and baseball in both high school and college.
"I believe that working together, we can make the Mariners a model franchise. I am looking forward to getting to work immediately, and developing a plan to reach our goal."
That plan better be great after Seattle became the first team with a $100 million payroll to lose 100 games.
Zduriencik's first task with the Mariners will be finding a new manager. John McLaren was fired in June and interim manager Jim Riggleman said he doesn't expect to return.
Mariners chief executive Howard Lincoln and team president Chuck Armstrong interviewed as many as 10 candidates in the last month, including Dodgers assistant GM Kim Ng -- who was trying to become the first female GM in the major leagues.
Instead, the Mariners went with Zduriencik's experience in traditional scouting.
"Jack is extremely well-respected throughout baseball," Lincoln said. "His track record in recognizing and developing young talent in Milwaukee was instrumental in the Brewers' steady improvement over the past several seasons."
There, he made the decision to draft catcher Jason Kendall with Pittsburgh's first pick in 1992.
Kendall, a three-time All-Star, is still a big fan of Zduriencik.
"Jack is just an unbelievable person. Obviously his track record speaks for itself," Kendall said earlier this year.