Ex president of Hull & Humber Chamber of Commerce and long-standing City passholder Phil Ascough said the first time City got promoted the players "were having parties all over the place".
Whenever Manchester or Liverpool played, thousands of away fans would come, ready to spend in restaurants and bars in the Avenues, Old Town and Marina.
"The top bars and restaurants would get players spending a lot of money on nice things.
"At one point you could get up to 4,000 away fans coming. Some would stick around and eat and drink and some would stay for the weekend," said Mr Ascough.
"It puts a place on the radar and makes people more interested.
"People who wouldn't normally hear about Hull would see it on Match of the Day and Sky.
"For Hull it was a massive deal - Leeds and Sheffield won't notice it in quite the same way as they have more going on than we have."
Director of Hull chartered accountants 360 Andy Steele said "you couldn't overstate the impact" being in the Premiership had, from positive media exposure, to the city appearing on the TV weather map, "not to mention the impact on people's health and well-being".
He said: "The BBC switched it on the back of City of Culture - I'm sure the likes of Channel 4 did it on the back of the Premier League. We were just exposed in the media far more often.
"I have clients who directly benefited from Hull City being in the Premiership - I am sure many would like them to get back there."
To the chagrin of fans, the team was relegated back to the Championship on May 14 2017, following their four-nil away defeat to Crystal Palace - just as Hull was celebrating its City of Culture year.
"The numbers are nothing like they were," said Mr Ascough. "(When we were in the Premier League) you were getting around 20,000 to 25,000 fans going into the stadium - sometimes last season it was less than 10,000.
"People are still going out to the pub before and after a match, but not in the same numbers and the visiting spend is lost."