The writer, director, producer and actor died Monday after a long battle with autoimmune inflammatory vasculitis.
"Michelle and I were saddened to hear of the passing of Harold Ramis, one of America's greatest satirists, and like so many other comedic geniuses, a proud product of Chicago's Second City," Obama said in a statement Tuesday.
"When we watched his movies -- from 'Animal House' and 'Caddyshack' to 'Ghostbusters' and 'Groundhog Day' -- we didn't just laugh until it hurt. We questioned authority. We identified with the outsider. We rooted for the underdog. And through it all, we never lost our faith in happy endings.
"Our thoughts and prayers are with Harold's wife, Erica, his children and grandchildren, and all those who loved him, who quote his work with abandon, and who hope that he received total consciousness."
"Deeply saddened to hear of the passing of my brilliant, gifted, funny friend, co-writer/performer and teacher Harold Ramis. May he now get the answers he was always seeking," Aykroyd said in an email to EW.com.
"Ghostbusters" director Ivan Reitman said in a separate statement to the website: "The world has lost a wonderful, truly original, comedy voice with the passing of Harold Ramis.
"He possessed the most agile mind I've ever witnessed. He always had the clearest sense of what was funny and how to create something in a new clever way. He was very generous about making everyone around him look better and smarter. Harold had an extraordinary impact on my career and I loved him like a brother. My heart goes out to his children, and his lovely wife, Erica. He will be profoundly missed," Reitman said.