Dan Sullivan is an American indie rock musician based in Chicago, Illinois. He started his musical career with self-titled (albeit mirrored) folk rock band Nad Navillus, (also styled NadNavillus), releasing three albums from March 1999 to November 2002, then reviving the project again in 2021. He was also a member of the short-lived post-rock project A-Z Consolidated, releasing one EP.
Sullivan was also known as a guitarist in Jason Molina's band Songs: Ohia from 2000 to 2003 and plays on the seminal "Magnolia Electric Company" LP. He founded metal band Arriver in 2005 but left the group in 2025.
He is a designer and woodworker and his company Navillus Woodworks was selected to provide chairs, stools and tables for the restaurant at the center of The Bear.
He is married to Puerto Rican artist Edra Soto, and the two are frequent creative collaborators.