The striker has penned a two-year extension to his New Douglas Park contract after impressing since making the move from Clydebank last summer.
Billy Reid's side face Dumbarton tonight and MacKinnon is keen to put some breathing space between themselves and the relegation battlers.
He said: "I am delighted to have signed a new deal with Accies that keeps me at the club for another couple of years.
"It was a big move for me last summer stepping up from the Juniors with Clydebank but having had my loan spell at Ayr and played more games at this level recently I feel I can make a real impact here.
"We have got a big couple of days coming up with the games against Dumbarton and Partick Thistle at home.
"It will be a tough one against Dumbarton tonight but it is a big chance for us to move away from the relegation battle and, hopefully, we can do that."
Victory tonight would be a timely boost to their survival bid and Sons boss Ian Murray hopes his side can haul themselves out of the bottom two.
He said: "I am not trying to prioritise games but tonight is a bigger game for us than Saturday was against Thistle.
"We rested a few players on Saturday with the view of the Hamilton game."