The 24-year-old is thought to have been hit in the arm when a person on a motorbike aimed at him as he stood outside Tup Tup Palace nightclub in Saint Nicholas Street, just metres from the cathedral.
The cathedral and surrounding areas were cordoned off after the incident at 10.30pm last night, but it's open as normal today.
Ian Britton from Premier's North East office was at the scene and said it was something "you don't normally expect".
He added that the area was still taped off.
The Dean of the Newcastle Cathedral told Premier it was a "real shock".
"We know the city is a lively place and sometimes there are difficulties, this is something quite unprecedented as far as we're concerned," Very Revd Chris Dalliston said, "when it does happen it's a real shock to the system."
He added that prayers would be said for the injured man: "We will be holding him very much in our prayers and indeed the whole community for peace, for security and for the police who have to execute their responsibilities in the city."
An eyewitness told the Newcastle Chronicle he seen the incident as he waited on his bike outside St Nicholas Cathedral.
"I saw a black motorbike pull up outside the coffee shop next door, La Maschera; right by where the kerb comes in for the parking spaces.
"It was a big bike, black all over and with what looked like a body kit on it so that you could not see its marking. But I could see it was a powerful sports bike; a Ducati or something like that.
"The rider was dressed all in black too - black helmet, visor, leather jacket, motorbike boots and blue jeans.
"It looked quite suspicious because he put his foot down and looked around; he stared right at me for a second.
"Then he started pushing at the handlebars of the bike as if it had stalled and he was tring to get it to start.
"I thought he had stalled.
"There was about 50 people queued up outside the club.
"The bike moved slowly towards Tup Tup and he was just past the kerb when there was a massive bang.
"I knew it was a gunshot. I used to go shooting with my family and it sounded to me not like a shotgun, but like a big handgun.
"The people outside Tup Tup did not react. but some girls in party dresses stood next to me started to scream."
Superintendent Chris Sharman said: "We know incidents like this cause concern and I would like to reassure the public that we are doing everything we can to trace the person responsible for this incident.
"Extra officers are in the city centre to help keep disruption to a minimum and offer reassurance to those who are in the city centre.
"If anyone has any information about this incident we would urge them to come forward and speak to us."
Ian Britton from Premier's North East office speaking to Dean of the Newcastle Cathedral, Very Revd Chris Dalliston: