Principal photography on the film, starring Justin Long and Michael Parks, is to begin Nov. 4.
Smith will direct his own script, which evolved from an episode of his long-running podcast with Scott Mosier.
"Tusk" is about a podcaster who "sets out to interview an eccentric, reclusive old seafarer, only to find himself a plaything in the gruesome plot of a deranged killer," a synopsis said.
Smith has previously indicated the podcaster in the movie will be held captive and forced to wear a walrus suit.
"Demarest is a director-driven company, and Kevin has always been at the top of our list of filmmakers with whom we want to work," Demarest Chief Executive Officer Sam Englebardt said in a statement.
Demarest Chairman William D. Johnson said, "We are hugely excited to see what results when Kevin applies his brilliant, twisted mind to classic horror film-making."
"I can't thank the good folks at Demarest enough for wading into weird waters with us," said Smith.
Smith's films include "Clerks," "Chasing Amy," "Dogma," "Jersey Girl," "Jay & Silent Bob Strike Back" and "Red State."