And Sean reckons a spell in England's Guinness Premiership can only aid his role in the national side's revival bid after a nightmare spell under sacked coach Matt Williams.
But Perthshire-born Sean, who scored a sensational try for Glasgow against Saints in the Heineken Cup last January, admitted in the Northampton Chronicle and Echo: "It was a tough decision for me to leave Scotland because I was well settled in at Glasgow. There are a lot of good boys up there, which made it even harder.
"But I felt I had to step up to the Premiership, which is where the top flight rugby is in Britain at the moment."
He was asked by Williams when it was announced he was joining Saints on a two-year contract whether he still wanted to play. Sean's reply was unequivocal.
"He didn't know if I had turned my back on Scottish rugby because of the way it was going," Sean said. "But I'm only 13 caps into my Scotland career and I don't want to turn my back on it.
"With Frank (Hadden) now in charge there is no problem although I can understand the idea of having all the Scottish players in Scotland because it would mean they can have access to whoever they want whenever they want.
"Frank is fine with me playing down here, there's no problem there, and I spoke to Budge (Pountney) at the start of the season and he is fine with it. He was saying the more internationals you have in Northampton it increases the profile of the club."
Sean has scored three tries for Scotland in his 13 appearances, but believes the best is yet to come.
"I am bringing a passion for my rugby here, that's what drives me on," said Sean whose younger brother Rory spent four years at Saints Academy before being shown the door by coach Wayne Smith after arriving late for a Wanderers match.
"I never see myself as the most flair player, you have got players like Carlos (Spencer) who is the man for the flair. I just do the donkey work.
"I have always been a direct player and no matter what club I am at I always give 100 per cent because as soon as you stop doing that there is such a depth of talent here you can find if you aren't pulling your weight you will be on your way."
Sean moved to Nottingham when he was 11, went to college at Sheffield before joining Rotherham and moving to Glasgow in 2003. And even when Saints were fighting against relegation he had no second thoughts about joining Saints.
"I had committed either way because I knew a lot of the boys like Bruce Reihana, Ben Cohen and Tom Smith had already done that.
"These boys are fully committed to Northampton so there is obviously a good spirit here. I just thought I would do the same and was coming regardless of relegation.
"The only way for Northampton is up. I was comfortable at Glasgow, which is nice and you are guaranteed your place, but you sometimes get complacent. I felt it was time to move on and step up the challenge."