The Hawks say Budenholzer will continue serving as the Spurs' top assistant through the NBA Finals. The Spurs completed a four-game sweep of Memphis in the Western Conference finals on Monday.
Ferry came to the Hawks last year after two years as vice president of basketball operations for the Spurs. With Budenholzer, Ferry now has his own coach after inheriting Drew.
Budenholzer, 43, spent 19 years with the Spurs, including 17 seasons as an assistant. He was the top assistant for coach Gregg Popovich the past six years.
"I have been extremely fortunate to be a part of the San Antonio Spurs organization for the last 19 years," Budenholzer said in a statement released by the Hawks. "I knew it would have to be a tremendous situation for me to leave and clearly coming to Atlanta as the head coach of the Hawks is perfect for me."
Kings sale approved
The NBA Board of Governors unanimously approved the sale of the Sacramento Kings on Tuesday to a group led by TIBCO Software chairman Vivek Ranadive. The league said in a statement that the "transaction is expected to close shortly."
After owners blocked the relocation of the franchise to Seattle earlier this month, the Maloof family reached an agreement to sell a 65 percent controlling interest in the Kings to Ranadive's group at a total franchise valuation of $535 million. Ranadive, who will have to sell his minority stake in the Golden State Warriors, becomes the NBA's first Indian-born majority owner.