At a glance
Half-Life: Source has a Mac version: Steam sells it for macOS. The Mac requirements list only Intel: on Apple Silicon Rosetta 2 runs it, and old Mac versions sometimes do not start on current macOS. Try it in Steam for Mac first.
Half-Life: Source came out on Steam on 1 June 2004, made by Valve.
What your Mac needs
The Mac requirements list only Intel.
Minimum macOS in the Steam requirements: 10.5.8.
Steam requirements list at least 1 GB of memory for Half-Life: Source.
How to play
Open Steam for Mac and install Half-Life: Source as usual.
If the Mac version will not start, you can install the Windows version through Uncork: download Uncork, sign in to Steam and install Half-Life: Source from there. We have not tested it ourselves.
The Windows version through Uncork needs a Mac with Apple Silicon (M1 or newer).
Half-Life: Source uses DirectX 7: Uncork renders it with its built-in graphics.
Half-Life: Source uses DirectX 9: Uncork renders it with its built-in graphics.