Ingram has become a regular on the international podium, winning world silver and European gold in recent years, but he was outwitted by Cuban rival Jorge Hierrezuelo Marcillis.
The 27-year old was a confident winner over American Dartanyon Crockett and Argentina's Jorge Lencina and entered the under-90kg final brimming with confidence.
British Olympic team members Colin Oates and Euan Burton were in the crowd to cheer him on, Oates spending time after his Games preparing with some members of the Paralympic team.
But Ingram went behind early on and didn't benefit from the officials decisions in a close-fought and low scoring encounter that went the distance.
“On the face of it silver is a great achievement, but I’m disappointed,” he said.
“I’m sure I’ll look back on it one day and be proud of silver, but right now with all the training and effort I’ve put in, it’s not what I set out for.
“I came here to win the tournament and I thought I was going to win the tournament. No-one ever sets out to come second.
“The match got away from me and I couldn’t pull it back. I felt like I was the better judo player, but I couldn’t control what was going on."
And there was disappointment for brother Joe, competing at his first Paralympic Games, who just missed out on the medals at under-100kg.
He dominated his opening round contest against Canada’s Tim Rees but lost to Korea's Gwang-Geun Choi, in a rematch of the 2010 World Championship final.
However, Sam Ingram's performance means the British judo team continued their Olympic success collecting two Paralympic medals – their best medal haul since the gold and two bronzes achieved at the Atlanta Games in 1996.