Terms have not been released, but Karl, an ESPN analyst, will get a four-year deal worth an estimated $15 million, sources said. The Kings will hold a formal news conference when the deal is finalized after All-Star Weekend.
Karl, who is attending a private funeral service for former North Carolina coach Dean Smith on Thursday, will take over as Tyrone Corbin's successor and Sacramento's third coach of the season starting next week.
Corbin was relieved of his duties Thursday, but will remain with the Kings in an advisory role, D'Alessandro said in a statement. Corbin had a 7-21 record since taking over after the Kings abruptly fired Mike Malone in mid-December.
"I have the utmost respect for Tyrone as a coach and person," D'Alessandro said in a statement. "He's a man of great integrity, a consummate professional that managed a difficult situation with class and professionalism. I look forward to continuing to work with Tyrone moving forward."
Sources told ESPN.com earlier this week that team officials informed Corbin that the Kings' games Tuesday and Wednesday in Chicago and Milwaukee likely would be his last two in charge.
Karl posted a tweet Thursday acknowledging his hiring.
The 63-year-old Karl -- who rejoined ESPN after leaving the Denver Nuggets on the heels of winning NBA Coach of the Year honors for the 2012-13 season -- ranks sixth all-time among NBA coaches with 1,131 wins. He coached in Cleveland, Golden State, Seattle and Milwaukee before his run with the Nuggets. After Karl joined the Nuggets midstream in the '04-05 season, he led them to a 32-8 finish.
All-Star power forwardDeMarcus Cousinsformally weighed in on the Kings' coaching situation before their game in Chicago on Tuesday night, insisting in an interview with ESPN.com that he has had no input for or against Karl. Two nights earlier he had gone on a cryptic postgame rant amid reports that he and his representatives were voicing opposition to Karl's hiring.
"I don't fire coaches or hire them," Cousins told ESPN. "Everyone knows I liked and respected Coach Malone. I didn't want [Malone's firing in December] to happen.
"I'm not involved in any coaching decisions right now. I've heard that George Karl is a great coach. If that is the direction that the organization chooses, I'll support it. Out of respect for Coach [Tyrone] Corbin, I hadn't planned on making any comments about what is rumored out there. But at this point I felt some things needed to be clarified."
He clarified his stance on the team's coaching situation further after Tuesday night's 104-86 loss to the Bulls, when he said, "All of [us] got thrown into this. To the best of our ability, we try to get it done. Work with what we have and try to leave the least amount of excuses possible."
Challenges Facing George Karl
Amin Elhassan discusses the challenges facing George Karl, who is expected to be named the next coach of the Sacramento Kings.
How Will George Karl Do With The Kings?
David Thorpe says George Karl's up-tempo style will play nicely with the Kings' roster.
Will Cousins And Karl Work In Sacramento?
Stephen A. Smith and Skip Bayless debate whether new Kings coach George Karl and center DeMarcus Cousins will work well together.