A host of rival clubs have been linked with moves for the 27-year-old tall, who has showcased his talents at both ends of the ground.
Richmond, Essendon and cross-town rivals Sydney are all reportedly in the mix.
GWS list boss Jason McCartney last week confirmed the club has put a long-term contract offer to Himmelberg, who has played 139 games across eight seasons with the Giants.
"We're pretty comfortable with where it sits, but clearly he hasn't signed yet," Kingsley told reporters on Thursday.
"We'd like that to happen sooner rather than later, but I'm sure it will play out.
"He's playing some really good footy, he's a really important part of our club, not just our team.
"We're really keen to keep him, as he knows."
Himmelberg has been used to good effect as a forward and defender during Kingsley's first season at the helm.
Kingsley said he is leaning more towards using Himmelberg in the backline against Fremantle at Giants Stadium on Saturday, with Dockers talls Jye Amiss, Josh Treacy and Luke Jackson all posing threats.
"But as we know he's a very, very capable forward and it will be needs-dependent for us," the coach said.
"He attacks both positions with great gusto, so he's comfortable playing at either end."
The Giants (5-8) remain hopeful of making a late charge towards the finals as they eye victory over Fremantle before the mid-season bye.
"Whether it's a capability this year or not, we'll play the games each on their merits and do the best that we can," Kingsley said.
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