Even his previous ambition of a career in broadcast journalism was thwarted as he didn't look old enough for the TV networks' tastes: 'I looked young. It was a credibility thing', he says.
The unconvinced should perhaps be directed to a CV, which has seen him rise from a Colorado country boy to managing director of a £10m fee income operation and be marked down as a rising star in the world's second largest PR firm.
Having started out as a reporter on a US local newspaper, Clark broke into the broadcast media, presenting an overnight music show on a local station. However his journalism career met a similar fate to those of a sizeable proportion of the PR community: 'Journalism was great, but there's no money in it,' he laments.
Instead he moved to New York, taking up a trainee role with healthcare and corporate agency Ruder Finn. It was there that he took the decision to focus on healthcare PR for much the same reason he arrived in the industry itself: 'If you asked Jesse James why he robs banks, he'd say it's where the money is. I could see there were exciting things going on in that area and decided to move there,' he says.
Despite believing that he would be 'a lifer' at Ruder Finn, his fascination for Britain led him to London, via two years in Paris, and the creation of CPR, the healthcare agency that was later to attract the attention of F-H.
Together with Steve Carroll and Moira Gitsham he founded and ran CPR, which was courted by all of the major PR networks in October 1999 before plumping for F-H.
It was, he says, exactly what one would want from an acquisition, evidenced by his ascent to the top of the UK operation when he could have relaxed on his share of the spoils: 'I thought "I'm still a young guy, I'd like to play on a bigger stage". Now I'm in it for more than just a pay cheque. I got a return on the blood, sweat and tears of doing CPR, but now I'm looking at what I can do to have an impact on the world of PR,' he says.
Before that grand ambition can be realised, Clark must first influence F-H, an agency whose UK business has been hit in recent months by the loss of major clients such as Nortel, a raft of redundancies, and the sudden departure of his predecessor as MD, Paul Blackburn.
The upheaval only seems to encourage Clark: 'Historically, F-H has faced challenges - there have been stops and starts. When people wonder why they should choose us, it's because we have something to prove. Wouldn't it be great to say that I came in at the point when the firm had taken knocks but then we sorted it out? It's almost harder to inherit a number one agency as there's only one way to go, and that's down,' he says.
Perhaps surprisingly, Clark readily acknowledges some of the criticisms levelled against the firm, principally that the agency too often focused on servicing US clients in Britain rather than acquiring native UK business.
That is likely to change: 'When we sold CPR to F-H, we went in with the principle that we wouldn't take any network business from F-H. Now we need to stand on our own two feet. Now if people see F-H on a pitch-list they're not too bothered. Fast forward one year and I want people to see we're involved and say "God, we'd better pull our socks up,"' he says.
With his relaxed manner, clients will most likely be won over. Long-time CPR client Cathy Kernen, head of global product PR at pharma giant AstraZeneca, says Clark is one of the main reasons she used the agency: 'He is strategic, smart and also a good human being. Some senior managers don't have time for you when they get promoted. Not Scott, at least we hope not. My guess is he's probably the same old Scott he was as an account executive,' she adds.
His achievement in rising so high so swiftly suggests it would be foolish to bet against an F-H resurgence.
While his past successes may not have gone to his head, they are enough to ensure he will prove the doubters wrong. His credibility will soon be beyond question.