When he first meets The Tick, he's trying to save him from being run over by a subway car. The Tick, thinking that Clark was just a well-dressed enzyme in the belly of the whale he thought he was in, resists, and the two are run over anyway (both survive). Afterward, Clark has to leave for a meeting, but he leaves his hat behind, allowing The Tick to track him down.
Clark, upon discovering that The Tick wants to be a superhero and is nigh-invulnerable, immediately begins to despise The Tick. His worst nightmares come true when The Tick is accidentally hired as the Weekly World Planet's new crossword writer, with his desk right next to Clark's.
The Tick proceeds to rummage through his stuff, stumbling upon a message-crystal left by his father, and triggering his secret Fortress of Fortitude to open. After that, Clark tries to politely tell Tick that the City is his, and that Tick should move on, but The Tick doesn't quite understand (or care).
To try to make it up to Clark, Tick bends his car up into an ashtray as a gift, which makes Clark go nuts and try to kill him. Tick breaks Clark's secret-identity hypnotic glasses, and stumbles off in a stupor. Not much is known of what Clark does after that.
Clark also makes a couple brief appearances in the first episode of the cartoon. He keeps trying to get to a phone booth or bathroom to change his costume so he can fight the Idea Men, but he can never find one that's vacant, so he's unable to do anything. The Champion, from the tv series, seems to be another version of the same character.