In February 2013 Steam for Linux was released. Sadly, “Steam for Linux” specifically seems to mean “Steam for Ubuntu”. Installing and running it on Debian is not as hassle-free as it should be. But fortunately it is possible at least, if you follow a few guidelines.

To install Steam it is not sufficient to download the official installer and run it. On Debian this simply won't work. But a kind person named Keith "GhostSquad57" created a Steam Installer for Wheezy. Download the ZIP file, extract it, install the .deb and you're ready to go.

If you get errors about Jockey missing, run this command (as root):

/usr/lib/steam/steam-debian-depends.sh

This will only happen on amd64 systems (which probably is the majority nowadays), an Nvidia card and you didn't use the official NVidia drivers. If you get errors about missing libGL.so.1 when running Steam, just install libgl1-nvidia-glx:i386:

apt-get install libgl1-nvidia-glx:i386

If it is not yet the case, you might have to add the i386 architecture:

dpkg --add-architecture i386

To query which foreign architectures are supported on your system run

dpkg --print-foreign-architectures