Ramos scored 10 minutes before the end of a first half largely dominated by Lucien Favre's visitors, who were unable to turn their possession into goals at the Olympiastadion.
Gladbach were unable to find a reply in the second half either as they fell to their fourth away defeat of the season, losing their captain Martin Stranzl to a red card in stoppage time.
The game was billed as a battle of two brothers - Ronny for Hertha and Raffael for Gladbach - but Hertha coach Jos Luhukay did not read the script, leaving Ronny on the bench and preferring Ramos in his attack.
It was a decision he would not regret either after seeing Ramos cap a lively opening with the only goal of the game in the 36th minute.
He rose to meet Per Skjelbred's free-kick with a precise header into the left-hand corner, taking the home side's first chance of the game after Gladbach had been the more creative up until that point.
Raffael twice went close for the visitors while Juan Arango saw his shot saved by Thomas Kraft in the Hertha goal as Gladbach tried to make their pressure pay.
The hosts had a second goal disallowed for offside just after the hour mark and, as the Foals stepped up their attempts to equalise, Hertha found themselves creating even more openings.
Gladbach became increasingly frustrated and Stranzl picked up two bookings in little over a minute to head to the dressing room a minute before the end to add to his side's misery.