Alan Schwartz, the last CEO of Bear Sterns, told CNBC's "Closing Bell" that Greenberg influenced many people's lives, including his own.
"[He] had a tremendous impact on my career and my life. I've often said that I learned more watching Ace than I learned from anything else in the business. There will never be another one like him," he said.
CNBC contributor Larry Kudlow also had fond memories of the late banker.
"Having worked for Ace Greenberg for many years, I can tell you he was a canny trader, a great businessman, and a shrewd judge of people," he wrote in an email. "He was also an incredibly generous philanthropist."