The visitors started brightly but the Spireites dominated most of the game and got their reward in the end.
Akwasi Asante finished low inside the area after substitute Nathan Tyson, making his first appearance in four months, picked him out.
Eastleigh thought they had taken the lead with 15 minutes to go through Danny Hollands but it was ruled out for offside.
Here are Liam Norcliffe’s ratings out of 10...
1. Chesterfield 1 v 0 Eastleigh
Tom Whelan returned to the starting line-up in Chesterfield's late win against Eastleigh. Picture: Tina Jenner. Photo: Tina Jenner
2. Grant Smith 7
A third clean sheet in four games. Smith did not have a save to make but his kicking was good and so was his handling from crosses. Photo: Dean Atkins
3. George Carline 7
A sound defensive performance and almost scored with two headers, one in each half. Photo: Tina Jenner
4. Fraser Kerr 8
A very good debut from Kerr who was announced as a Spireites player earlier in the day. He slotted into Will Evans' position at right centre-back comfortably. A couple of crunching tackles in the first half would have drawn applause had fans been at the Technique. He was strong in the air and played the ball out from the back. Photo: Tina Jenner