"This is a bittersweet deal for me as the head coach because Charlie was obviously someone I was really excited about having in here," Haley said.
A formal announcement will come Monday, but a source told NFL Network insider Jason La Canfora on Saturday that Weis will remain the Chiefs' offensive coordinator during their playoff run.
Weis, hired to be Notre Dame's head coach five years ago after now-outgoing Florida coach Urban Meyer turned down the Irish to join the Gators, is joining Will Muschamp's first staff in Gainesville.
Before Weis accepted the job, Kansas City's WHB-AM cited a source in reporting that he was considering it because his son, who's graduating from high school this year, will work in the football office for Muschamp while attending Florida. According to the radio station, Weis' son was set to work under Muschamp at Texas, but he will go to Florida now that the coach is there.
Haley confirmed Sunday that Weis' son will be at Florida, too.
"Charlie's a family guy," Haley said. "He can go to Florida and be with his son, who's gonna get into coaching. This is a great situation for Charlie, and I respect it 100 percent, and we respect it 100 percent."
Weis told The Kansas City Star that speculation of a fractured relationship between Haley and himself was untrue.
"I almost get offended when people say that," Weis said. "People always want to look for a different angle for why you're doing this. Scott (Pioli), Todd (Haley), Clark (Hunt), they brought me in to Kansas City when I was sitting at home in South Bend. I'll be forever grateful for the opportunity I had to come here as the offensive coordinator and I'll always wish them well.
"But this decision had absolutely zero to do with relationships in Kansas City."
With the Chiefs (10-6) headed to the playoffs as the AFC West champions, Weis won't go on the road recruiting for Florida for at least a week, but he will be able to call recruits.
The Chiefs' offense has made strides in its first season under Weis, entering Sunday's game ranked first in the NFL in rushing (167.5 yards per game), 28th in passing (192.1 yards per game) and ninth overall (359.6 yards per game).
"Charlie is a professional," Haley said. "Charlie has been through a similar situation back a few years ago. There were some potential distractions ... that he, being a professional, did his job to the fullest to help the team win a Super Bowl. I have the utmost confidence that's what will go on here."
The Associated Press contributed to this report.