"He is a proven NBA talent who has played an essential role in a winning NBA organization," Bucks owner Herb Kohl said in a release distributed during the third quarter of Friday night's game in Boston. "We look forward to John's contributions to our franchise."
The move had been expected, and opposing coach Doc Rivers of the Celtics addressed it before the game. Told that the Bucks hadn't made it official yet, Rivers said, "It's official. So, let's make it official."
Detroit won at least 50 games in all seven seasons Hammond was by the side of GM Joe Dumars, with six division titles, five straight appearances in the Eastern Conference finals and an NBA title in 2004.
"I had the pleasure of working under one of the best executives in the game today in Joe Dumars, and I thank him for the opportunity he gave me to be a part of Detroit's winning tradition," Hammond said. "The Bucks are a history-rich franchise with amazing fans and I look forward to the challenge of bringing a championship back to Milwaukee."
Bucks coach Larry Krystkowiak said before Friday night's game that he hadn't heard the news, but that it wouldn't be a surprise to him.
"I was anticipating that something was going to happen pretty soon, but I hadn't heard any news at this point," he said. "Just trying to get a win."
Asked about reports that Hammond would be looking to bring in a veteran coach, Krystkowiak said, "Until I hear those words from his mouth ... at that point, if that were true, I'd be disappointed."
The 53-year-old Hammond spent 10 years as a college coach and worked as an assistant in the NBA with the Timberwolves, Los Angeles Clippers and Pistons.
"He's a great guy, he really knows the game," Rivers said. "He coached the game and been upstairs -- that's a great combination because he'll have feelings for coaches."
The Bucks were 26-52 heading into Friday night's game in Boston, clinching the third-worst record in the Eastern Conference. They let Larry Harris leave after he asked if his contract would be renewed at the end of the season.
Sources told ESPN.com's Marc Stein that Hammond's first task in Milwaukee will be hiring a veteran coach to help the Bucks make a firm assessment of their talent after a group expected to compete for a playoff berth in the Eastern Conference woefully underachieved in Krystkowiak's first full season on the bench.
Sources said Hammond was expected to make a strong push to hire former Pistons coach Rick Carlisle. Working as an ESPN analyst this season after leaving the Indiana Pacers, Carlisle is also widely considered as a strong candidate to coach the Chicago Bulls next season.
Sources told ESPN.com last month that Krystkowiak's dismissal at season's end was considered a certainty no matter who succeeded Harris because of Kohl's desire for more experience on the bench.
The Bucks and Harris parted company on March 19 after Harris, with his contract expiring in June, initiated a series of meetings aimed at either securing an extension or bringing a halt to the growing uncertainty surrounding his lame-duck status before the end of the regular season.
Player personnel director Dave Babcock had been handling the day-to-day operations and draft preparation during the search for a replacement. The team's owner, Sen. Herb Kohl, said Babcock was not a candidate for the permanent job because he wanted someone who would take a fresh look.
Milwaukee did show interest in new Knicks president Donnie Walsh as well as TNT analyst Doug Collins. Yet the Bucks knew landing either of them to replace Harris was a long shot given New York's desperation to hire the longtime Pacers executive and Walsh's strong urge to take over his hometown team, as well as Collins' reluctance to leave the TV arena.
Hammond also initially resisted the Bucks' overtures but eventually decided that this was the right time to leap after working in the Pistons' front office since the 2001-02 season, operating closely with Dumars in the construction of a roster that has delivered seven consecutive 50-win seasons and five straight trips to the Eastern Conference finals, highlighted by Detroit's run to the championship in 2004. Hammond has also been an assistant coach in Detroit and previously worked on the bench and in the front office with the Los Angeles Clippers and the Minnesota Timberwolves.
In addition to Walsh and Collins, other candidates Milwaukee considered include Phoenix Suns vice president of basketball operations David Griffin, two veteran GMs in Rick Sund and Billy King, Washington Wizards executive Tommy Sheppard and the two top aides to R.C. Buford in San Antonio: Dennis Lindsey and Dell Demps.
Although the Pistons were reluctant to lose Hammond to a division rival, Dumars still has a strong staff that includes director of basketball operations Tony Ronzone and director of basketball administration Jeff Weltman.
Information from The Associated Press and ESPN.com senior writer Marc Stein was used in this report.