Speaking in front of his mother's house in Cambridge, Mass., Curtis said he was amazed and thankful for the efforts that were to get him home.
"In the days following my release on Sunday, I have learned bit-by-bit that there have been literally hundreds of people -- brave, determined, big-hearted all over the world -- working for my release. They've been working for two years on this," said Curtis. "I am just overwhelmed with emotion. I am also overwhelmed with one other thing and that is total strangers have been coming up to me and saying, 'Hey, we're just glad you're home. Welcome home. Glad you're back. Glad you're safe.'"
Curtis arrived home Tuesday. He was believed to be held by the al-Nusra front, a radical Syrian rebel group linked to Al Qaida.
Curtis' release comes a week after the murder of American journalist James Foley by the Islamic State (IS). In a video posted on YouTube, an IS militant beheaded Foley and threatened to kill journalist Steven Sotloff if the U.S. did not cease airstrikes against its weapons caches and command centers.