"Netflix was a no brainer when we first went into it." Icahn said in a CNBC "Fast Money Halftime" interview. "You couldn't compete with Netflix because they were starting the year with like $2 billion flowing into them, and Reed Hastings did a great job in building it up."
"I think the competition is somewhat easier if you see the secular change going on where they're building service, where they can go over the top, and there's going to be cable competition," Icahn added.
Icahn also said he believes Apple may be in the same position Netflix was, or maybe even in a better one. "I just don't see how … you compete with Apple because of the great ecosystem they've built."
Icahn Enterprises owned approximately 1.4 million Netflix shares at the end of the first quarter, according to Reuters.
Netflix shares dipped shortly after Icahn tweeted the announcement, and were up slightly in midafternoon trading.
The stock split will come in the form of a dividend of six additional shares for each outstanding share, Netflix said. It is payable on July 14 to stock owners of record at the July 2 close. Trading at the post-split price will start July 15.
The move was anticipated this year after Netflix voting shareholders approved a share reauthorization, a preliminary step toward a split.
The company's stock has risen about 100 percent this year and nearly 60 percent in the last 12 months.
—CNBC's Jacob Pramuk contributed to this report.
Disclosure: Carl Icahn holds a large stake in Apple.