TNS clinched the title with a 0-0 at Connah’s Quay and wrapped it up with five games to spare at the home of their closest rivals.
They now have an unassailable 17-point lead at the top of the league meaning the title will remain at Park Hall.
Harris has been at the helm of the club for over 25 years and has seen every one of his managers win a league title.
He said now is the time to ‘make their mark’ on European competition.
Harris said: “I’m so happy for everyone in The New Saints family. I would like to congratulate our manager Craig Harrison, the entire coaching and backroom staff, and of course all of the players who have performed outstandingly throughout the season.
“Together we deserve to be champions.
“I’m thrilled for all of the players and most importantly for our supporters, it is a magnificent achievement.
“Since my journey with The New Saints FC began we’ve continued to lead the way in the Welsh Premier League and it has been another incredible season to remember with some outstanding moments throughout the last 12 months.
“We have the JD Welsh Cup final to look forward to at the end of next month and we will be doing everything possible to make sure we add to our league title success and end the season with more silverware in our hands.
“We won’t stop there though, we will continue to grow and come back even stronger next season.
“We want to make our mark on European football and take this club to where it belongs. I have every belief that we can compete at that level.
“Getting to the group stage is very, very difficult in the Champions League. But I believe getting into the group stages of one of the three competitions is well within our grasp in the next two or three seasons.
“Our ability to compete off the pitch is growing but if you also look at what we’re doing within our academy, we’re attracting the best young kids in the local area and the club as a whole is thriving.
“ We have seen that by the continued success of the first team which is continuing to strengthen and progress. On winning the title, Harrison said: “It’s fantastic. The lads have done so well to win the league with five games to go.
“We’ve got a lot of hard workers, great professionals, and they aren’t getting sick of winning and that’s something I’m big on.
“”I’m delighted to win my 15th trophy as a manager and now we can start planning for the 16th and European competition again next season.”