Rodwell - booked in the first half for simulation, which led to Bruce and Poyet's ugly spat - nodded in Patrick van Aanholt's cross on the goalline with 13 minutes left as the two strugglers shared the spoils.
Van Aanholt's ball appeared to be crossing the line anyway, but Rodwell, whose header looked to have flicked his arm, made sure Sunderland broke a four-game scoring drought in all competitions.
Sunderland goalkeeper Costel Pantilimon then made an excellent reaction save to keep out a header from Dame N'Doye, who had opened the scoring in the first half, as the visitors held on for a point.
The headlines are sure to focus on Bruce and Poyet's confrontation, though, after the Sunderland boss was sent off for kicking a container filled with water bottles following Mike Dean's decision to book Rodwell.
Bruce was then prevented from running at Poyet and there was an angry exchange of words as the latter made his way down the tunnel.
Sunderland, now without a win in five Premier League matches, were without winger Adam Johnson after he was suspended by the club following his arrest on Monday.
Wes Brown started again for the visitors after the red card he was wrongly given in Saturday's 2-0 loss at Manchester United was rescinded, but he had a part to play in Hull's 15th-minute opener.
After a lengthy delay following Brown's foul on Ahmed Elmohamady, Tom Huddlestone drove in a low free-kick that N'Doye smartly flicked beyond Pantilimon and in.
Rodwell, one of four Sunderland inclusions, was booked in the 36th minute after trying to win a penalty for the visitors.
And that led to the game's flashpoint, as an enraged Poyet booted a drinks container and was subsequently sent to the stands by referee Dean.
Poyet disputed the decision and then wandered over to Bruce, appearing to look for a handshake, before the Hull manager reacted angrily and tried to run at the Sunderland boss.
An official held Bruce back in dramatic scenes, but once play finally resumed, Hull looked unfortunate not to win a penalty after John O'Shea manhandled Nikica Jelavic - returning from a knee problem - in the area.
O'Shea's header nearly crept in for a Sunderland equaliser just before the hour mark, while at the other end, N'Doye blasted a first-time effort well over following a promising Hull counter-attack.
Tensions rose once more when a cynical Lee Cattermole kick on David Meyler resulted in the latter squaring up to the Sunderland man.
Cattermole, who will be banned for the next two matches as a result of his latest booking, was quickly replaced by Ricky Alvarez as Sunderland bolstered their attacking options.
Yet it was Hull who seemed closer to a goal as N'Doye nodded over and left-back Andrew Robertson shot just wide from 20 yards.
Jake Livermore then spurned a good chance, shooting at Pantilimon following a clever Elmohamady cut-back, and Sunderland made Hull pay with their 77th-minute equaliser.
Anthony Reveillere fed Van Aanholt down the left and his cross floated over Hull goalkeeper Allan McGregor before Rodwell applied the finishing touches.
Hull almost restored their lead immediately, but N'Doye was denied by Pantilimon as Sunderland claimed a valuable draw on the road.
