His father was Zachary Smith, who would sometimes appear to him through a time portal. After Smith died, the Critic made peace. His brothers were Ask That Guy and Rob Walker, who was a dinosaur.
At one important moment in the Critic's timeline, he joined a game of poker being played by Rob, The Ghost of Christmas Future, and 80's Dan. Up until that point, he'd been bitter about never having any interactions with other people, only for Rob and Dan to point out that he was welcome all along.
Also of note, he once saved his entire reality from the dangers of The Plot Hole.
Among his arsenal was included his trusty handgun, as well as the Nostalgia Signal.