The hosts went ahead in the 22nd minute when Carl Fletcher drilled home from the edge of the area but Stead came off the bench to earn Roy Keane's side a vital point with his 68th-minute strike.
The Pilgrims were reduced to 10 men late on when Darcy Blake saw red but held on to avoid going bottom.
The hosts had former Plymouth and Ipswich striker Paul Mariner in the dugout alongside manager Paul Sturrock for the first time after his appointment as head coach following two decades working in the United States.
Plymouth were also able to welcome back Kari Arnason following a chest infection but were without Bradley Wright-Phillips, who remains out with a knee problem.
Jon Walters made the Ipswich starting XI despite previously being rated very doubtful after sustaining a ankle strain as Town were denied victory late on in their 1-1 draw with Watford on Tuesday night.
The hosts looked to apply some early pressure but Gary Sawyer and Jamie Mackie saw shots blocked before Pablo Counago produced the first shot on target at the other end, goalkeeper Romain Larrieu gathering comfortably.
Grant Leadbitter then unleashed a strike from the edge of the hosts' box but failed to keep his effort on target.
A good chance then fell to Ipswich when Sawyer's cross reached Rory Fallon, but the striker failed to keep his header down.
He made amends however when he played the ball through for Fletcher, who unleashed 20-yard thunderbolt.
Town were dealt a further blow just minutes later when Gareth McAuley was forced off due to injury, paving way for Alex Bruce to make his return following a groin injury, while Fallon was replaced by Cillian Sheridan shortly after.
Leadbitter's curling strike from the edge of the area was parried by Larrieu and Plymouth went in ahead at the break.
Walters had the chance to pull Town level shortly after the break but failed to place his header on target after latching onto David Wright's cross.
Keane then turned to Stead just before the hour mark bringing him on for Pablo Counago and enjoyed the fruits of his decision just 10 minutes later.
The striker was first to react to Sawyer's slack backpass and made no mistake in slotting home from 12 yards.
Karl Duguid looked to restore the hosts' lead but saw his strike from the edge of the area parried away by goalkeeper Asmir Begovic.
Carlos Edwards then fired over the bar before Blake received a straight red for a foul on Walters in the 84th minute.