The Living Tribunal is the second in command of the universe. Let that sink in for a moment. The only person above him is number one on this list. He existed before, and despite, the Big Bang (Jeez, I wish I could stop bringing up the Big Bang, but it's a big part of these larger-than-the-universe characters). He gives the ultimate judgement calls on all universes, not just one. That excludes universes created by other characters, but still, that's a lot of power.
Even Infinity, Eternity, and Death listen then the Living Tribunal speaks. Hell, anyone named the Living Tribunal deserves attention. That wouldn't be a bad name for a kid. If anyone ever made fun of him he could say, "you dare speak to the Living Tribunal that way?" You can't pull that off with a normal name.