Wycombe have dropped back into League One less than 12 months after winning promotion via the play-offs but Ainsworth could not be prouder of his players' efforts in the second tier.
The Chairboys signed off in style by beating Middlesbrough 3-0 for a fifth win in their final eight games – though they went into Saturday knowing they needed to win by at least 13 to stand even a theoretical chance of survival.
And their manager, who has been linked with the vacant managerial position at Preston, is already looking forward to mounting a promotion push with his current employers next term.
Ainsworth said: "There are no mixed emotions – I'm just really proud of what we've done.
"The long-term planning for Wycombe was to get into the Championship but it wasn't supposed to happen this season.
"It might seem a strange thing to say because we've been relegated, but finishing third from bottom in the Championship is one of the proudest moments in my career.
"It's the highest the club has ever finished. We've spent a lot of time trying to get into League One, so to be playing in the Championship has been a dream really."
Ainsworth will oversee some rebuilding work in the summer but unlike in the past, when he has had to sell players to finance any investment, this time he will be working from a position of strength.
He said: "For the first time, we've got the ability to turn down bids for our players. We can keep the players we want to keep and then go out and try to build.
"We've always really been a selling club but now we can go out there and try to get some better players. We know we've got the ability to hold on to our better players and I'm excited about next season. I think we've got the opportunity to make a real noise."
Middlesbrough manager Neil Warnock was understandably disappointed at his side's final-day capitulation but did not feel the 3-0 defeat should overshadow a campaign that has seen the Teessiders successfully rebuild after only avoiding relegation in the final game of last season.
Warnock said: "I'm not going to knock them today. We were poor today but overall, to finish 10th after where we were when we came in, I think it's been a fabulous achievement.
"I think they've really done their best. You could see the limitations today, and you could see the players that were missing. We have to look forward now.
"I haven't got to think about today, really. To finish 10th, I'm delighted. Now we just need a bit of luck with the recruitment and with the players coming back from injury.
"If that all goes well, we'll have a very good chance of finishing higher than 10th next season. I don't think you can promise anything because I don't think anybody knows what your recruitment will be.
"We'll need a bit of luck. I don't think I'm being disrespectful to the lads that have been here, but we've finished 10th without really having a striker this season."