Adam Armstrong's second half strike took City into the Play-Off places in a match that they dominated with numerous goal-scoring opportunities.
Sky Blues boss Tony Mowbray made two changes to the team that lost narrowly at Scunthorpe last week, with Ryan Kent making his first full start in place of Marcus Tudgay. Jim O'Brien also came into the side for Ruben Lamerais.
The game started at a leisurely pace but almost burst into life after seven minutes. Jacob Murphy was released on the left hand side and his cut back found Armstrong, but his shot was charged down at the last moment.
City were having the lions share of possession but were being frustrated by the Spireites, who were happy to sit back and defend. Jacob Murphy stung the hands of keeper Tommy Lee with a low drive after a quarter of an hour, but the shot was easily saved.
The Sky Blues were nearly in on 20 minutes. City broke and Kent found Armstrong out wide with a lovely ball. He squared it looking for Murphy but the ball zipped just behind him for what would have been a tap-in.
There was an even better chance to come six minutes later, when Armstrong bore down on goal. He got in the area and cut inside on his left foot, but ballooned his effort over the top.
A carbon copy attempt from O'Brien sixty seconds later produced the same result. Another left footed shot inside the area saw the ball sail over a second time.
It was a first half where City looked more threatening but could not find the cutting edge.
It was a different story at the start of the second period though, as League One Player of the month Armstrong fired in his sixth of the season five minutes after the restart.
He did well to get the ball out from his feet after being fed by Murphy and struck the ball across himself and into the far corner from 16 yards.
City nearly made it two soon after as Murphy struck from 30 yards, Lee doing well to parry as the ball bounced awkwardly.
Chesterfield had been anonymous for much of the contest but they had a goal disallowed on the hour when Sylvain Ebanks-Blake tapped the ball home when the ball was diverted into his path following a deflected free-kick, but he was judged offside.
The Spireites were finding their way back into the match and Mani Dieseruvwe had a curling effort from 20 yards brilliantly touched wide by Lee Burge on 66 minutes.
It was the City number one who was becoming the busier of the two keepers and he was at full stretch to claw out an in-swinging Chris Herd free kick with 20 minutes to go.
But from that save the Sky Blues broke away with Murphy, who ghosted past two defenders and fired at the near post, his shot saved well by Lee.
The game was not yet safe and Marc Antoine-Fortune was brought on as the Sky Blues looked fore their second. Kent nearly found it with six minutes left when he went on a mazy solo run but slipped at the crucial moment as his effort bumbled into Lee's hands.
With three minutes remaining Dieseruvwe was sent off as he picked up a second yellow for deliberately handling a cross into City's area to divert it towards goal.
In injury time Kent had a goal disallowed for offside as he played a one-two with Murphy before slotting home.
Chesterfield could not create any more opportunities and City were victorious in their only home league game this month. Focus now turns to an away trip at Bury next Saturday.
Attendance: 11,003 (841 Away)
Coventry City: Burge, Ricketts, Martin, Johnson, Stokes; Vincelot, Fleck; O'Brien (Fortune 75'), Kent, Murphy; Armstrong (Lameiras 84').
Subs: Charles-Cook, Phillips, Morris, C.Thomas, Tudgay.
Chesterfield: Lee, S Hird (Banks 77'), Jones, C Hird, Morsy, Evatt, Gardner (Ariyibi 41'), Ebanks-Blake, O'Shea, Novak (Dieseruvwe 45'), O'Neil.
Subs: Cairns, Raglan, Gnanduillet, Humphreys.