In a statement, perennial heavyweights the Sixers said they were disappointed with Hopes' decision after unveiling him as Greg Shipperd's replacement in early May.
The retired allrounder, who played 96 white-ball internationals for Australia, has signed a three-year deal that puts him in charge of Queensland's men's sides in the Sheffield Shield, One-Day Cup and BBL.
"I wrestled with this decision as I was, and still am, very appreciative of being offered the Sixers role earlier this year," former Queensland captain Hopes said in a statement.
"However, to have the opportunity to take on the head coaching program with Queensland and live in Brisbane again was too good to miss."
He replaces former South African international Johan Botha, who resigned from Queensland Cricket about a month after Hopes was announced as Sixers coach.
As a player, Hopes led Queensland to titles in the Sheffield Shield in 2012 and One-Day Cup in the 2012/13 and 2013/14 seasons.
He was a foundation player and captain of the Heat, before beginning his coaching career upon retirement in 2016.
Hopes is currently an assistant to head coach Ricky Ponting at the Washington Freedom, and has worked with the BBL's Hobart Hurricanes, as well as in the IPL.
Cricket NSW now turns its attention to finding a new coach for the Sixers, having last month appointed Andrew Flintoff to lead cross-town rivals the Sydney Thunder.
Former Test wicketkeeper Brad Haddin takes charge of the Blues in the Shield and One-Day Cup from this season.
"While the club is disappointed by (Hopes') decision, we understand the significance of this opportunity for him and his family, and we wish him all the very best," the Sixers said in a statement.
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