In his new role, which he takes up on August 15, he will succeed Alastair Machray, who was named as the new editor of the Liverpool Echo in May.
Rob, (39), began his newspaper career at the Warrington Guardian.
He was also news editor of the Bradford Telegraph & Argus and the Derby Evening Telegraph, before moving into production journalism.
He joined the Liverpool Echo four-and-a-half years ago when he was appointed design editor.
Rob said: “The Daily Post has a superb 150-year history in Wales and is brimming with confidence since its relaunch.
“I look forward to working with such a talented team and, together, we will ensure that the Daily Post will continue to grow and provide a voice for the people who are proud to call Wales their home.
“I have had a fantastic time during the past four years in Liverpool and I and my wife Julie, are thrilled about this new challenge and the prospect of making a new home near the paper’s base in Llandudno Junction.”
Georgina Harvey, Trinity Mirror’s managing director, regional newspapers, said: “The Daily Post in Wales has enjoyed great success since its relaunch in March 2003, and has been among the UK’s top regional titles in terms of circulation performance.
“Rob’s breadth of experience will be invaluable in taking the title to even greater heights.”
Mark Thomas, assistant editor of the Liverpool Daily Post, will become acting editor until Jane Wolstenholme’s return later this year.