It was almost two years ago that Brad Pitt was in town – along with dozens of cast and crew, hundreds of extras, a media frenzy and any number of zombies – shooting World War Z.

Like many big-budget Hollywood films – its costs have been put at between £135m and £161m – World War Z has had a colourful, tangled life, including several rewrites and, at a rumoured cost of £13m, seven weeks of reshoots. On Thursday, however, it will finally be shown in cinemas. Many people in Glasgow can hardly wait but Hamish Walker has a special reason to look out for World War Z. A production executive at the Glasgow Film Office (GFO), he was among those involved in the discussions that brought producer/star Pitt, director Marc Forster (Quantum Of Solace) and a small army to the city in 2011.

"The first time we heard from World War Z," he says outside Glasgow City Chambers, which was a backdrop to the high-profile shoot, "was that they were looking for offshore supply vessels, the kind that serve the oil and gas industry. We told them, 'We don't have too much of that, but try our colleagues in Aberdeenshire.' Glasgow is part of the Scottish Locations Network, and we all work closely. That seemed to be that.

"Glasgow has a database of potential locations, with more than 530 registered locations, and after a while we got a call from someone with the film, who'd spotted the on-ramp on to the M8 and thought it looked like a US-type freeway and asked, 'What would be the possibility of filming there?' We told him we were open for business. Colleagues in council departments said it would be possible if the producers could afford to put traffic diversion measures in place.

"We sent them some photographs, and after a while the film people asked about broad, city-centre streets. We sent details of streets around the international financial services district, such as Cadogan Street and Bothwell Street.

"Michael Harm, the film's location manager, came up and we met outside the City Chambers on a wet and windy day. He said, 'Let's walk.' He was taking photographs as he walked, and looked at everything on the way to the [financial services district], towards the Kingston Bridge.

"He reported back to the production people and he came straight back up. We set up meetings with our colleagues in traffic management and he outlined what he hoped do to.

"There then was a weekend meeting with the director and some of the creative personnel. At that time the proposal revolved around Bothwell Street, but the cinematographer [Oscar-winning Robert Richardson] didn't think it would work, for various reasons.

"On the Monday morning we came into the office and Harm rang and said, 'The bad news is the director and cinematographer don't think it can work – but the good news is, they love George Square.'

"Traffic management reckoned it could work but it would need a fairly major closure of streets. From then on, it was all go," says Walker.

It was a stroke of luck that the council occupied all of the set, though nearby businesses had, of course, to be notified of the disruption that would be coming their way. "We knocked on doors, told the owners what would be happening.

"The shoot went smoothly – there was very little grumbling from people. Everybody seemed to be excited by the prospect of Brad Pitt filming. It took us by surprise, just how much an event it did become, but in retrospect it would be hard to avoid that."

Walker, who is 50, has extensive experience. In 1997 he was part of Scottish Enterprise's Film Unit, a small operation that oversaw the birth of Scottish Screen from the component parts of Scottish Film Council, the Scottish Film Production Fund, Scottish Screen Locations, Scottish Broadcast and Film Training.

He has now been with GFO for 15 years, and has first-hand knowledge of several of the big film and TV productions that have been shot, partly or wholly, in Glasgow.

As he puts it: "You never know what will turn up on any given day. I can be helping researchers from London TV companies identify Glasgow's landmarks and pointing them in the right direction for filming permission, or I can be responding to a nationwide search for a specific location like, for instance, 'Brutalist-style housing with interesting and traffic-free features -'

"In any case, it's a chance to get the thinking cap on in terms of what exists in Glasgow that we can throw into the mix – and, to a certain extent, a chance to show off the city I've lived in all my life."

He looks back fondly at his involvement with World War Z. The trailer looks good – Glasgow can be glimpsed now and then – and the scene in which zombies cause a panic-sticken stampede in front of the City Chambers, right where Walker and I are standing, should be one of the film's highlights.

The UK and Scottish film-location business is tight-knit, Walker says. "I don't think there's any doubt that, with [location scouts] having seen what can be achieved in Glasgow, in terms of the city as a location and in what it has to offer architecturally, and how co-operative the city is towards film crews, this will not go unnoticed."

As Jeremy Kleiner, producer of World War Z, said a while back: "The cooperation we had from the Glasgow Film Office and indeed from across the city council made it all possible, and the people of Glasgow were incredibly welcoming. It's been a very successful shoot here." n

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