The Image Comics founder said that when people sue you, it means that your work "matters".
"I just went, 'Robert, what you're about to get involved in is a pain in the ass, take it from me'," McFarlane told Newsarama.
"But there is a silver lining in that you're doing something that matters. Because nobody ever sues anybody over something that doesn't matter."
McFarlane further explained: "So, you know, if your book was selling four copies, it wouldn't matter what agreement everybody thinks they have. Nobody cares. They only sue when there's money on the table. There's money on the table because you're doing something successful.
"You have to get a thick skin, and in a weird way, if people keep coming at you, and lawyers keep coming at you, that means you're doing something successful, that you're enough of a target for them."
McFarlane settled his long-standing Spawn lawsuit with Neil Gaiman in January.
Kirkman is currently being sued by former Walking Dead artist Tony Moore over compensation for his contribution to the hit franchise.