Dubke, 47, who was tasked with helping shape the president's message, served in the post for only about three months.
He resigned May 18 but offered to stay on until the end of Trump's first foreign trip as president, ABC News has learned.
According to Priebus, Dubke "will remain on board until a transition is concluded."
"Mike will assist with the transition and be a strong advocate for the president and the president's policies moving forward," said Priebus.
Dubke's last day has not yet been set.
Dubke's resignation may serve as an opportunity to revamp Trump's communications team, which has frequently come under criticism since he took office in January.
ABC News' Katherine Faulders and Jonathan Karl contributed to this report.