The 36-year-old former assistant coach at St Mirren and Cowdenbeath has helped Michael O'Neill steer his fifth seeds to a place in the finals in France.
"It makes me proud, but I'm also disappointed Scotland didn't qualify," Macphee told BBC Scotland.
"We're the first team from pot five to win a group."
Macphee had an unremarkable playing career, with spells at East Fife, Forfar Athletic and Queen's Park before he embarked on a footballing scholarship in the United States.
His playing career took him to Romania with Braila and Japan with Kariya before turning to management and leading Cupar Hearts to the Scottish Amateur Cup final in 2007.
Macphee then worked with Danny Lennon at Cowdenbeath and St Mirren, where he helped the club win the League Cup.
"That season, we made a strong start to the league then beating Celtic in the cup semi-final at Hampden was fantastic and going on to lift the Cup against Hearts," he said.
Northern Ireland manager O'Neill was impressed by Macphee's performance analysis work in Paisley and soon brought him into the international set-up.
"Unless you're a Barcelona, a Real Madrid, or a Manchester United, where you can quite simply have your own playing identity because you know your players are better than the opponent, there is an element there you can disregard the opponent," he said.
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"I know from conversations with Jonny Evans, Alex Ferguson - apart from the Champions League - didn't pay any attention to the opponent.
"He filled the players with belief that 'Manchester United play this way and we are better'. At the biggest clubs in the world, you can play this way.
"St Mirren are clearly not one of them and Michael learned from speaking to players and other managers about my work."
While Scotland will be watching from home next summer, Northern Ireland won their group ahead of Romania, Hungary, Greece, Finland and the Faroe Islands despite a limited group of players to pick from.
Among their squad are players from the likes of Fleetwood Town and Doncaster Rovers, while seven players are currently playing in Scottish football.
"I don't think it's necessarily a surprise that Michael O'Neill has managed to turn Northern Ireland around," said Macphee, who also scouted for Mexico at last year's World Cup in Brazil.
"I think a lot of people don't know what he achieved with Shamrock Rovers.
"He managed to win the league twice there, but the most remarkable achievement there for Michael - he took them into the Europa League.
"He did that with players on 42-week contracts. That's basically part-time footballers he's taken into the group stage.
"I know from discussing with him the budget was only about £450,000, which to give you idea of scale is half that of any Scottish top-flight club."
Macphee, who runs sport tours and football academy businesses, added: "It's not a case of managing expectations.
"We've already achieved something which people will see as remarkable.
"The team spirit in the group of players is unbelievable.
"The humility from the top players like Jonny Evans and Steven Davis, just because of the gulf in what the players earn, everybody's equal and we will keep that unity between staff and players."
Austin Macphee could be the only Scotsman at Euro 2016 after being part of the coaching set-up at Northern Ireland.