The Royals announced the new contract on Monday. Moore exercised his option for 2011 and the Royals added '12, '13 and '14 to the deal. Terms were not disclosed.
"Although it has been a disappointing season," said Royals president Dan Glass, "I believe we are heading in the right direction and Dayton is an important part of the process."
The extension comes with the Royals in last place in the American League Central with a 50-80 record going into a series with Oakland A's on Monday night. The team had been projected to possibly approach the .500 mark but has been hit by injuries and sub-par performances.
"As the saying goes, you're never as good as you think you are and you're never as bad as you think you are," Moore said. "I'm encouraged and feel very secure in what we're doing to build our organization and make it very strong."
Moore was hired as senior vice president of baseball operations and general manager on May 30, 2006, succeeding Allard Baird. The 2006 team lost 100 games but improved to 69-93 in 2007 and 75-87 in 2008.
The extension makes it clear that the Glass family, headed by owner David Glass, is satisfied with the moves that Moore has made in the last three-plus years.
"We've had tremendous support from David and Dan Glass and I'm grateful for that support and honored to work with a very talented and dedicated group that's focused on bringing a winner here to Kansas City," Moore said.
He noted that the Glasses have enabled him to create 16 new positions in the baseball operations sector and that 12 of those hired have been part of World Series-winning teams.
The Royals' crash after an 18-11 start came as a surprise, but it was accompanied by early injuries to third baseman Alex Gordon, shortstop Mike Aviles, center fielder Coco Crisp and to others later in the season.
"We were very encouraged when we left Spring Training that we could win 78 to 84 games and, if everything went well, to compete in the division, but it didn't happen," Moore said.
Run production flopped, the bullpen foundered and the defense was very spotty.
"The bottom line is that players haven't performed the way that we felt they would," Moore said. "And when you look at the group we had, they all had a track record that you could hang your hat on and, for whatever reason, they haven't performed at that level."
During his tenure, Moore has signed such free agents as pitchers Gil Meche, John Bale, Juan Cruz and Kyle Farnsworth, outfielders Jose Guillen and Willie Bloomquist and catcher Miguel Olivo, selected closer Joakim Soria in the Rule 5 Draft, and traded for pitchers Brian Bannister and Kyle Davies, second baseman Alberto Callaspo, designated hitter Mike Jacobs, shortstop Yuniesky Betancourt and outfielder Crisp.
And there were deals he didn't make as he looked to the future.
"We haven't traded Joakim Soria, we signed him long-term; we haven't traded Zack Greinke, we signed him long-term," Moore said. "We have Alex Gordon and Billy Butler for potentially the next three or four years and certainly other players in the pipeline that we've held onto instead of trading for other Major League players."
Moore repeated his assertion of earlier this summer that Hillman was in solid standing as the Royals' manager.
"I think Trey's done a tremendous job this year -- the leadership that shows day-in and day-out, the energy that he puts into this team and the thought and the pride that he puts in," Moore said.
"I feel that Trey, as we sit here today, is the absolute right person to lead our baseball team in the dugout at the Major League level. With all of the injuries, the setbacks and disappointments we've had this year, I think Trey did very well."
Moore came to the Royals from the Atlanta Braves, where he'd been since 1994, working his way up from area scouting supervisor to assistant general. A native of Wichita, Kan., Moore is a graduate of George Mason University.
He officially took over the GM's job on June 8, 2006. Since then, the Royals have had a record of 242-317.
"I thought we did as good a job as we possibly could on building on the successes of Allard Baird and what he did here and, hopefully, we'll continue to do that and add to it," Moore said.
Armed with a contract through the next five seasons, he doesn't see any change in his administrative style.
"Have we made mistakes? Absolutely," Moore said. "But as [special assistant] Mike Arbuckle reminded me the other day, 'If we're not making any mistakes, we're probably not being very aggressive.'"
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.