Robert Snodgrass headed in the crucial winning goal with quarter of an hour remaining at the Riverside Stadium to ensure Villa moved level on points with sixth-placed Sheffield United.
It was a tight affair on Teesside but Middlesbrough, after winning back-to-back games beforehand, narrowly lost out as Pulis’ reign started with a loss.
The former West Brom boss only took over on Boxing Day, when he was in the stands to watch the victory over Bolton, and he was a frustrated figure in his technical area throughout the 90 minutes.
Pulis only emerged from the tunnel as the game kicked off, so there was no time for any special introduction to the supporters. He made a statement or two in terms of his first selection but they failed to have the desired effect.
Regular full-back Cyrus Christie was only named on the bench and an opportunity was handed to Ryan Shotton down the right. The former Stoke man, who worked under Pulis there, was asked to use his long throw to regularly deliver balls into the box.
The aim was to see target-man Rudy Gestede, back in the side for the first time since August, make a nuisance of himself in the area. He had a couple of first-half efforts but nothing to really trouble goalkeeper Sam Johnstone.
Aston Villa, without a win in their five previous December fixtures, caused occasional problems, although Snodgrass’ free-kick at Darren Randolph was the only effort recorded on target in the opening 20 minutes by either side.
Middlesbrough striker Britt Assombalonga headed wide a Grant Leadbitter corner, but the best chance of the half stemmed from the home team’s tendency to gift possession to the visitors.
Shotton and Daniel Ayala had already done that when Ben Gibson followed their lead and played a pass to former team-mate Albert Adomah. The winger’s low strike rolled straight into Randolph.
Middlesbrough’s best first half chance was when Jonny Howson struck a volley straight at Johnstone after running on to Gestede’s knock down; it was also their first effort on target and Pulis clearly wanted more.
But Villa looked more dangerous after the restart. James Chester headed onto the roof of the net when he met Conor Hourihane’s free-kick from the right, while Randolph did well to turn a low drive from Jack Grealish behind for a corner.
Pulis’ first substitution was to introduce Adama Traore. His power and pace lifted the Riverside and his team-mates, and a couple of direct runs created a couple of half chances.
But it was the man who replaced Traore at Villa, Adomah, who created the winning goal. The Ghana winger, who swapped clubs in August 2016, sent over a teasing deep cross for Snodgrass to dive and head inside the bottom corner.
Pulis said: “I thought Villa did well, they played with a back four and five in front and never let us get in behind.
“I wanted to play with two forwards, see what Rudy Gestede and Britt Assombalonga were like together with Stewart Downing and Martin Braithwaite - and the quality they’ve got you’d hope we’d create opportunities.
“I just thought we were very, very slow at times. We needed to move the ball quicker and Adama Traore when he came on livened it up. He carried the ball and he livened the crowd, which is important in home games. He was definitely a plus.
“This squad is bigger than the one I left at West Brom, too many in my view, some you know and some you don’t know. I need to assess the group.
“Steve (Gibson, the chairman) spent an absolute fortune in the summer and out of respect to him I really have to be prudent with what I do and don’t, not make rash decisions.
“If it takes a bit of time it takes a bit of time but I want to be fair to Steve because he’s spent a lot of money on the squad.
“There’s players within the group that I’ve got to find out about. I’ve got a chance to watch a lot of games quickly. The squad is definitely too big. I don’t like big squads.”
Middlesbrough: Randolph, Shotton, Ayala, Gibson, Friend, Downing, Howson, Leadbitter, Braithwaite (Traore 57), Assombalonga (Fletcher 79), Gestede (Bamford 69). Subs Not Used: Konstantopoulos, Guedioura, Christie, Baker.
Aston Villa: Johnstone, Elmohamady, Elphick, Chester, Hutton, Jedinak, Snodgrass, Onomah (Grealish 37), Hourihane, Adomah (Bjarnason 90), Hogan (Hepburn-Murphy 75). Subs Not Used: Steer, Bree, Doyle-Hayes, O’Hare.
Referee: Andrew Madley (West Yorkshire).