"It's the duty of the board to do what's best for the shareholders and bring them in," he said on CNBC's "Halftime Report." "As far as I'm concerned, this wasn't going to happen at this company if we hadn't appeared, and it's basically a sad commentary that you have these companies that actually could be sold for the benefit of shareholders.
"Shareholders made over $2.5 billion in value since I've been there."
CNBC reported Tuesday that Family Dollar insiders had been skeptical of a takeover bid by Dollar General, which, sources said, had a "clear runway" to make a deal a year ago—and at a lower cost.
Instead, Dollar Tree purchased Family Dollar three weeks ago for $8.5 billion in a deal that created a single company with more than 13,000 stores.
On "Halftime Report," Icahn took issue with the idea that he was to blame for a deal with Dollar General falling through.
"The company for some reason chose to bring it up and blame me for the fact that Dollar General wasn't interested, which is completely disingenuous," he said.
Icahn also said that he had profited on the Dollar Tree deal, selling his 9-plus percent stake down to a 3-plus percent stake.
"I didn't sell much cheaper than where it is. I'm not disappointed. I made $200 million. I never look at the last dollar," he said. "I've sold a lot of things too cheaply, but at the end, as I say, you know, my record's good enough to me. So, I'm not unhappy at all with the situation."
Family Dollar did not immediately respond to a request for comment.
Icahn, a frequent critic of corporate governance, also noted a larger issue.
"However, I want to make a point that this is one of the quintessential problems that's wrong with corporate governance today and why shareholders aren't getting these benefits because boards can go in and literally stymie these deals," he said.
"We're a very sizeable shareholder," he said. "I think those followers that read my tweet when it was—what, $450, not too long ago—the ones who bought it and held it should be happy, should read my tweets more. They should become followers. So, I think they should be awful happy with this one. We haven't sold a share."