Dirk Strider, character in the web comic "Homestuck"
Dirk Diggler, fictional porn star in the movie "Boogie Nights"
DirkCalloway, character in the movie "Rushmore"
DirkPitt, character in a series of novels by Clive Cussler
Dirk Mann, character in Disney Channel's "Bizaardvark"
Dirk Gently, delightfully quirky character from DouglasAdams books and TV show Dirk Gently's Holistic Detective Agency