A super first half strike from Lee Evans in only the seventh minute was added to by a close range finish from Billy Clarke towards the end of the game.
The victory meant Parkinson's men ended their scheduled league fixtures for the 2015/2016 campaign having won nine of their last twelve games, conceding only four goals in the process.
Parkinson said: "We had a number of targets today (Sunday) - reaching 80 points, getting seven home league wins on the trot, and to get some momentum to take into the Play-Offs - to achieve all three is really important.
"It was a very professional approach from the lads. These sort of games are always difficult because no matter what you tell players, there is always that chance of them having one eye on next week.
"The way they went about their work was terrific though. In football, it can be difficult to turn the tap on hot and cold so that is why it was very important that we took that good form into the Play-Offs."
Following the final set of results of the regular league season, City now know they will play Millwall in the Play-Offs semi-finals. The first leg will take place at the Coral Windows Stadium on Sunday (15 May - kick off 12:15pm).
Parkinson added: "Next Sunday, the fans will be so important. They have played such a significant part in getting us to where we are now.
"The real business of the season starts once again for us now and I would urge as many of our supporters as possible to get your tickets. Let's get as many fans as we can into the ground because we want to utilise that twelfth man advantage at home next Sunday.
"When the lads come out and the ground is as full as it was today, it is always a very special occasion. We need another special atmosphere around the ground next Sunday."
The only downside from City's game with Chesterfield was the sight of Reece Burke being replaced at half time due to injury. Josh Cullen was also substituted towards the end of the game after taking a whack to his leg.
Parkinson said: "He (Reece) strained his groin when he struck a ball down in the line in the first half.
"It is a blow for him and for us but we have a very good deputy in Nathan Clarke. Once again, he was extremely unlucky not to start today and he was excellent when he did come on.
"Josh got a dead leg so we took him off as well towards the end, hopefully he doesn't seem too bad. We hope Reece will be ok as well because he's been magnificent for us but we'll have to wait and see."