After Joe Willock had seen his strike disallowed after a VAR check at the Tottenham Hotspur Stadium, Malick Thiaw prodded home his fourth goal of the season in first half stoppage time to give Eddie Howe's side a deserved lead at the end of a half in which they dominated.
Archie Gray volleyed Spurs back onto level terms after the restart, but Ramsey's well-taken second with just over 20 minutes remaining gave the Magpies their first win in six and alleviated some of the pressure on Howe's charges, who move up to tenth in the Premier League table.
The United head coach made four changes to his side for the trip to the capital, with Dan Burn, Jacob Ramsey, Anthony Elanga and Anthony Gordon coming into the starting 11 at the expense of Lewis Hall, Sandro Tonali, Jacob Murphy and Yoane Wissa.
Elanga in particular started brightly in North London, and was instrumental in forcing a couple of early corners before crossing for Sven Botman to head over.
Xavi Simons dragged a shot through Kieran Trippier's legs and into the sidenetting for the hosts, but Willock went even closer for the Magpies, firing just wide of the target after some neat build-up play involving Harvey Barnes, Gordon and Bruno Guimarães.
Elanga could have felt a little aggrieved not to have an assist to show from his energetic start, with Barnes backheeling a low cross from the Swedish international straight at Spurs stopper Guglielmo Vicario. Ramsey then latched on to a Burn knock-down just over quarter of an hour in, but didn't connect cleanly with the strike. He tried again before the half hour, whistling a powerful shot just past the upright as United continued to press.
A couple of minutes before the break, United thought they had moved in front. Ramsey's through ball released Willock down the middle, and the former Arsenal man cut inside and buried a shot beyond Vicario and into the bottom right-hand corner. It was a superb finish but after a protracted VAR check, the goal was ruled out for offside, with Willock's forehead ever so fractionally ahead of the last man when Ramsey played him in.
It was a very tight call but Newcastle's disappointment didn't last long. Willock had a hand in Thiaw's opener - his cross for the German international was an excellent one - and after the centre back's header was parried by Vicario, Thiaw followed in to prod home the deadlock-breaker deep in stoppage time.
The Magpies started the second half well too, with Gordon and Willock constant threats and Elanga seeing a penalty appeal waved away after falling under the challenge of Djed Spence. Ramsey then saw two efforts blocked from successive Guimarães corners before Simons felled Willock as he shaped to shoot. Again, referee Anthony Taylor was unmoved.
Spurs' best move of the game brought their first real chance seven minutes after the restart. It owed much to the work of Gray on the right, with the youngster skipping past a challenge and driving into the box before squaring for substitute Mathys Tel, whose finish was high and wayward. Pape Matar Sarr then forced Nick Pope into a smart save with a drive from distance as Thomas Frank's side rallied.
They were rewarded for their improved showing in the second half when Sarr turned a corner back into the six-yard box and Gray hooked in a leveller from point-blank range to buoy Frank's men, who had looked firmly second best in the first half.
It didn't deter United, though. After Gordon's mazy dribble brought him back into the Spurs box, his lay-off into the path of Ramsey was perfectly weighted - as was the former Aston Villa man's low finish with his unfavoured left foot, which gave the Magpies the lead once more.
And it was a lead they held despite some late Spurs desperation, with Micky van der Ven lashing over, to secure a welcome victory ahead of two crucial FA Cup and Champions League clashes to come with Aston Villa and Qarabağ FK respectively.
Newcastle United: Nick Pope; Kieran Trippier, Sven Botman, Anthony Gordon (Will Osula 88), Harvey Barnes, Malick Thiaw, Anthony Elanga (Sandro Tonali 75), Joe Willock (Nick Woltemade 88), Dan Burn, Bruno Guimarães (c) (Lewis Hall 90), Jacob Ramsey (Jacob Murphy 75)