|Faction||Black Mesa Science Team|
|Status||Alive as of May 17th 200X|
|Location||Black Mesa Research Facility (Barney's Mind)|
|Actor|| Harry S. Robins (game audio)|
- "Carry my guns for me, douchebag!"
- ―Barney Calhoun
Walter shows almost no personality at all when first meeting with Barney after saving him from being trapped in a cargo train by HECU Grunts (this is because his voice lines are all recycled audio clips from the game). However during the Barney's Mind finale, he is voiced by Corky64 and his personality takes on a much more abrasive tone towards Barney.
It is unclear what happens to him after he is shot unconsious by the jet during the Barney's Mind finale, though he most likey survived.