In a match of few opportunities, a dour first half had just two half chances from Andy Booth headers, it was Knight who broke the deadlock with a goal fashioned from nothing in the 66th minute.
He cut inside from the left touchline and hammered the ball between a clutch of defenders and into the bottom corner of the net with Mark Goodlad unsighted.
The goal was Knight's 6th of the season and marked the fourth consecutive senior Town game in which he has scored - repeating Wayne Allison's feat in September 1998.
The Terriers should have pushed on for a second but, having been given fair warning during the match of Port Vale's attacking capabilities, Town began to defend deep again.
The introduction of Danny Webber in a very attacking second half for Port Vale saw the Terriers pegged back into their own area regularly towards the end of the game as they struggled to weather repeated Vale attacks following aimless long clearances upfield.
The now inevitable equaliser came in the 80th minute from Mark Carragher's cross. The ball eventually reached Michael Cummins who despatched the ball beyond the despairing dive of Martyn Margetson.
Town could still have won the game when Nathan Clarke came up for a corner with 2 minutes to go but fired high from 6 yards out after Kevin Gray's header was cleared off the line.
There was still time for Steve Jenkins to make clearing tackles in the final moments to preserve the point - one from McPhee looked especially dangerous for the Terriers.
The day had ended in a fourth consecutive league draw and with Andy Booth reportedly arguing with Steve Jenkins as they went down the tunnel.
Read Mel Booth's match report on Monday or give us your comments on this match by using the response form on the right or the message board below.
Port Vale (4-4-2): Goodlad, Carragher, McClare (Webber 58), Burton, Brisco, Cummins, Brooker, McPhee, Ingram, Burns, Rowland
Subs not used: Delaney, Dodd, Burgess, Donnelly
Scorer: Cummins 80
Town (4-4-2): Margetson, Jenkins, Gray, Clarke, Heary, Schofield, Holland, Mattis, Irons (Hay 77), Booth, Knight
Subs not used: P. Senior, Dyson, Moses, Macari
Scorer: Knight 66
Referee: Mike Jones (Chester)
See subsequent pages for match points
91 mins: Schofield went into the box after a great cross by Knight but he couldn't find Chris Hay.
90 mins: 2 minutes of added time were announced.
89 mins: Steve Jenkins tackled Stephen McPhee as he lined up a shot on goal.
88 mins: Town won a late corner. Nathan Clarke skied the ball from 4 yards after an earlier attempt had been headed off the line from Kevin Gray!
86 mins: Port Vale were still asking questions of Town's defence as they laboured to restore their lead.
83 mins: Chris Hay was pulled up for a late challenge.
81 mins: A long ball was caught under his own goal by Goodlad with Schofield lurking.
80 mins: Martyn Margetson dived but couldn't stop Michael Cummins from levelling the scores with a header from an incisive cross by Matt Carragher. Town had let the lead go once again!
79 mins: Kevin Gray cleared from McPhee but the ball came back from midfield through Port Vale. Town were defending deep and hitting aimless balls upfield once again.
78 mins: McPhee's cross was cleared by Thomas Heary - 3 Port Vale players were waiting had the cross been completed.
76 mins: Port Vale lined up an attack from the edge of the Town area as the game moved from end to end.
75 mins: Leon Knight was tackled by Sagi Burton as Town shaped up for a sweeping attack.
74 mins: Gray headed clear under pressure from Brooker and Town struggled to contain the Port Vale attack which ended with the ball coming off the top of the bar with Margetson struggling to get back after Danny Schofield had missed a tackle.
70 mins: Nathan Clarke shepherded the ball out of play after a great tackle by Dwayne Mattis. Town were determined not to concede another late equaliser.
69 mins: Andy Booth was denied a chance of the ball by Rae Ingram.
67 mins: Irons crossed deep and found Danny Schofield but his pass for Knight was intercepted by a panicked Vale defence who cleared before the on-fire Knight could reach the ball.
67 mins: Knight was helped off the field and had to wait patiently for permission to return to the game.
66 mins: Leon Knight cut inside from the left touchline and hammered a ball between a clutch of defenders and into the corner of the net to put the Terriers into the lead! Knight was injured by Steve Rowland moments later and required treatment.
65 mins: Danny Schofield reached a long ball before it went out but his cross for Knight was claimed by Goodlad.
63 mins: Leon Knight was back defending as their hosts won a corner.
62 mins: Town were playing deep again as Port Vale showed good skill to force the Terriers onto the back foot.
60 mins: Vale were camped in the Town half but Jenkins stood firm and cleared.
59 mins: Brian Horton decided to include the prolific Man Utd youth striker Danny Webber as Vale changed things to break the deadlock with a three man attack.
58 mins: McPhee hit the ball over the top for Brooker to chase but the ball went too far and was cleared.
57 mins: Kenny Irons struck the 30 yard free kick well and brought a good save out of Goodlad.
56 mins: Vale spread the play as they tried to attack once again but Town countered with Knight attacking well in conjunction with Schofield but the little Town striker was pushed by Burton.
54 mins: Sagi Burton tried to curl one past the Town wall but he sliced his effort well wide.
53 mins: Clarke gave away a free kick in a dangerous position when he fouled Sean McClare.
52 mins: Gray beat Brooker in the air but Vale continued to press until Thomas Heary combined with Chris Holland to deny Rae Ingram a chance to get past.
48 mins: Paul Rowland's effort was headed out by Gray!
47 mins: Dwayne Mattis cut into the penalty area and drilled the ball wide of the post after Knight laid the ball off to him.
46 mins: Schofield and Knight combined well - Knight's shot was blocked but Town eventually won a corner from their pressure.
Andy Booth had a pair of headers go close in this largely eventless first half. Thomas Heary's 2nd minute cross was headed wide by the big striker and Chris Holland provided a 40th minute header which also went wide but any goal might have been disallowed by the referee as Booth was climbing on a defender at the time.
Heary also put in a decent defensive performance along with Martyn Margetson who warded off the probing Port Vale attacks.
45 mins: Leon Knight had chased the ball down but was tackled. Andy Booth tried a first time ball to put Knight back in but he was offside again.
44 mins: Paul Brooker was being well marshalled by Thomas Heary as both sides continued to press for chances on goal.
40 mins: Andy Booth's header across the face of goal was just wide after a period of Town pressure. Booth seemed to be pushing his marker so a goal might not have stood.
38 mins: A Vale counter-attack was stopped by Kenny Irons who fed the ball to Andy Booth but Sagi Burton was doing well in defence.
36 mins: Leon Knight was adjudged offside - a close decision.
34 mnis: Thomas Heary headed Paul Rowland's crosss awat with Brooker lurking.
34 mins: Danny Schofield went on a run into a pack of Vale defenders and eventuall knocked it clear
33 mins: Gray cleared a set piece up against Sagi Burton.
30 mins: Holland crossed for Andy Booth but the ball was cleared. His hard-working almost opened up another chance.
28 mins: Liam Burns fired over the bar. Town were defending deep and inviting their hosts to counter-attack at will.
27 mins: Andy Booth won his header but the ball fell to Leon Knight who couldn't make use of the ball
26 mins: Gray blocked well from McClare and Town continued to resist the slowly mounting Vale pressure.
25 mins: Leon Knight conceded a free kick against Matt Carragher after climbing all over the Port Vale defender.
24 mins: Andy Booth beat the offside trap. Leon Knight was available and he went round two players but slipped and allowed the Vale defenders to clear.
24 mins: Knight miscontrolled the ball on the edge of the area and the ball was subsequently booted clear.
23 mins: Kevin Gray needed to rely on Nathan Clarke to help him out after a slip-up in defence.
22 mins: Town were reverting to the long ball for Andy Booth but Port Vale were coping well.
20 mins: Schofield tried an ambitious shot which drifted wide for a goal kick.
19 mins: Danny Schofield went up for a cross and the back post and won a corner.
18 mins: Leon Knight was frustrated as his great run was not rewarded with an incisive pass from Andy Booth.
16 mins: Sean McClare took a free kick which Margetson rose to catch under pressure.
15 mins: A free header from a Vale corner went straight into Margetson's hands - a warning to the static Town defence.
14 mins: Leon Knight was limping after taking a knock. Port Vale went on the counter and Brooker had an excellent chance to shoot on the goal but the ball ran beyond his reach.
14 mins: Margetson saved easily from McClare who was getting too much space in midfield. Mattis put Knight through but the little Town striker was easily offside.
12 mins: Schofield broke up a Vale attack at the expense of a throw-in.
12 mins: Knight's flicked header caused some consternation in the Vale defence but it was eventually cleared after Knight gave up the chase for the loose ball.
10 mins: Vale continued to build, dictating the game at their own pace, as Town dropped off and allowed their hosts to play.
8 mins: Vale built down their left side but Holland won the ball off Brooker.
7 mins: Thomas Heary conceded a corner during a patiently constructed Vale attack.
6 mins: Another Vale attack was eventually repelled by Town who pressed hard and almost created an opening themselves.
5 mins: Vale's first attack was wasted by Stephen Brooker who headed behind Margetson's goal.
4 mins: Jenkins was body checked just outside the Vale area after a great overlap with Schofield. Irons wasted the free kick which flew over the top of Andy Booth's head.
3 mins: Andy Booth headed wide after a run by Chris Holland allowed him to lay off the ball to Thomas Heary whose enticing cross opened up the chance.
2 mins: Andy Booth was offside after a lively and attacking Town start.
1 mins: Andy Booth's shot came of Sagi Burton for a corner after some great work by Irons and Holland.
1 mins: Irons' long pass was cleared by Matt Carragher before Knight could reach it.
Town were completely unchanged from their game against Brentford in midweek. Port Vale manager Brian Horton lost loan striker Chris Killen, who was recalled back to Manchester City. He replaced him with Danny Webber from Manchester United and the young striker started on the bench for the hosts. Clyde Wijnhard travelled with the Town players even though he was some way from fitness.