David Cardoza says he was always confident the Cobblers would beat the drop into non-League football, but only after appointing Chris Wilder as first-team manager.
Town picked up 31 points from 20 games under Wilder to secure their place in the Football League.
Relegation is estimated to cost a club in the region of £1m, when central League funding and solidarity payments from the Premier League stop in the second year after the drop.
The club would also have had to significantly downsize its youth department, which has produced players such as Ivan Toney and Lewis Hornby in recent years.
But Cardoza was not concerned during the final stages of the campaign that it would be one that ended with the team playing outside of the League for the first time since 1920.
“It finished well but it was terrible up to Christmas,” said the chairman.
“Once Chris came in I was confident the situation would sort itself out.
“We’d like to have had it done earlier but we did it anyway; that was Chris’s remit and we look forward to next season now.
“When we conceded to Wimbledon in injury time, that was the only time that I thought our luck had run out.
“The Bury defeat was the end of the world for everyone, but we kicked on straight away at Accrington and then it went on from there.
“Bury was the lowest point of the second half of the season, there were obviously low points earlier in the season because we all sat there and thought ‘something is very wrong’, and there was.
“But the important thing is we got out of it and now we move on.”