The Royals also hired former Toronto Blue Jays manager John Gibbons as bench coach to complete the six-man staff.
Dave Owen, who was bench coach for manager Trey Hillman last season, will become the third-base coach.
In a related move, Luis Silverio, who was the third-base coach last season, accepted a position as special assistant to player development. Silverio and hitting coach Mike Barnett were not offered contracts to remain on the coaching staff.
The other three coaching positions remain intact: Bob McClure, pitching; Rusty Kuntz, first base, and John Mizerock, bullpen.
Seitzer, 46, was the Arizona Diamondbacks' hitting coach for the first half of 2007 before being dismissed. That's been his only other Major League coaching experience.
"He was an exciting player and fan favorite during his days as a Royal," general manager Dayton Moore said, "and he possesses the same amount of passion and energy as a coach."
In a 12-year Major League career, Seitzer also played for Milwaukee, Oakland and Cleveland and had a .295 batting average in 1,439 games. He appeared twice in the postseason for the Indians, including the 1997 World Series.
For the Royals, he was an All-Star as a rookie in 1987 when he batted .323 with 15 home runs and 207 hits. He was second in the American League Rookie of the Year voting to Oakland's Mark McGwire. Seitzer and ex-catcher Mike Macfarlane have operated a baseball and softball academy, Mac-N-Seitz, in Kansas City since 1996.
Gibbons, 46, spent the last five years as the Blue Jays' manager and compiled a 305-305 record before being dismissed June 20. The Jays' best finish under his watch was second place in 2006.
"There's a lot that goes on in the game, probably more than people sitting there watching the game realize. Things happen fast," Gibbons said of the bench-coach role. "I think I can definitely help Trey. I know the league and I've been around long enough to know the different teams a little bit. But it comes down to what he wants out of me."
An ex-catcher for the New York Mets, Gibbons coached and managed in the Mets' organization from 1991-2001 and joined the Blue Jays' coaching staff in 2002. He took over as manager in August 2004 when Carlos Tosca was dismissed.
Gibbons, Hillman and Owen are fellow Texans. Gibbons is from San Antonio and managed against Hillman for years in the Minor Leagues.
Gibbons' Toronto tenure was marked by two highly publicized clashes with players Shea Hillenbrand and Ted Lilly.
"There were a couple of things that happened up there. I'm not proud of either one of 'em," Gibbons said. "It's just something that happened. Actually, I'm just an easy-going, fun guy, I think. I enjoy going to the ballpark every day and having a good time."
Silverio has been in the Royals' organization for 34 years, the last six on the Major League coaching staff. His main focus in the newly created position will be to help young Latin American players' transition into pro baseball.
"Luis has a terrific working knowledge of our organization, and his ability to communicate our values to [Latinos] will only make the players more comfortable as they grow within our system," Moore said.
Silverio, 51, was pleased to take the newly created position.
"This gave me the opportunity to continue to do something for this organization, something that I wanted to do," he said. "I'm happy and looking forward to the challenge of doing my little part in making this organization better."
Silverio said he'd travel to the Dominican Republic Academy and to the Royals' Minor League clubs during the season. He can draw on his own experience when counseling the kids. He signed in the Dominican in 1973 and was a 17-year-old outfielder when he began playing the Royals' system.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.