An emotional Conlan told RTE after the fight: "I was boxing the ears off him, I don't know how it went against me.
"I thought the first round I won easy by boxing him. Second round I completely annihilated him standing in close to him. Third round the same, probably a bit closer than the second. I put a serious shift in.
"He was completely surprised (to win). He roared like he'd won the Olympic gold... He knows he didn't win. The American kid's going to pick him to shreds and I wouldn't be surprised if they rob him too."
An official from the International Boxing Association (AIBA) said later: "Michael is a current world champion and he came here with high expectations. His disappointment is massive, we can all understand that. It's his personal judgment.
When the dust settles, the only thing we have that matters is family thanks for the amazing support 2day everyone! pic.twitter.com/tWF7hhsE3d
"There were judges sitting there, professionals who take responsibility for these things. Why is there this mistrust all the time?"
Later in a statement from the IABA, they said that they would be seeking a review of the judging and scoring processes.
"The IABA fully understands the frustration expressed by our athletes and coaches regarding the outcome of some of the bouts at the Games particularly given the split decisions that went against three of our athletes, the casting decision which saw Katie lose and the controversy around Michael Conlan’s defeat earlier today," the statement read.
"We do not have an option to appeal decisions at the Olympic Games. IABA do however believe that in light of events in Rio, it is in the best interests of amateur Olympic boxing that the scoring and judging process is reviewed. We will look to work with other national federations and AIBA to ensure that this happens.
"The boxers and the coaches are devastated and our primary concern at the moment is to support each of those who competed at Rio and who have dedicated the last four years of their lives to pursue their Olympic dreams."
Heavyweight Evgeny Tishchenko's gold-medal victory over Vassiliy Levit in a widely criticised decision is likely to be a catalyst for change during the International Boxing Association's next evaluation of its judging.
AIBA executive board member Tom Virgets told The Associated Press on Tuesday that while he wouldn't offer a personal opinion on the decision, he expects the sport's judging criteria to evolve before the 2020 Olympics.
"Every fight will be analyzed, some with a stronger eye than others," Virgets said