It means that Trump can push his unique brand of narcissism, conspiracy theories and calls for domestic terrorism after he was banned from several platforms last year.
The app was available to download shortly before midnight ET and was automatically downloaded to Apple devices belonging to users who had pre-ordered the app.
Apparently, though some users reported either having trouble registering for an account or were added to a waitlist with a message: "Due to massive demand, we have placed you on our waitlist."
Trump was banned from Twitter, Facebook and YouTube following the attack on the US Capitol by his supporters, after he was accused of posting messages inciting violence.
Truth Social is led by former Republican US Representative Devin Nunes, Trump Media & Technology Group (TMTG) and is based on the myth that the media is silencing conservative voices.
"This week we will begin to roll out on the Apple App Store. That's going to be awesome, because we're going to get so many more people that are going to be on the platform", Nunes said in a Sunday appearance on Fox News' "Sunday Morning Futures with Maria Bartiromo".
"Our goal is, I think we're going to hit it, I think by the by the end of March we're going to be fully operational at least within the United States", he added.
Nunes was on the app urging users to follow more accounts, share photos and videos and participate in conversations, in an apparent attempt to drum up activity, according to a person with knowledge of the matter.
TMTG remains mostly shrouded in secrecy and is regarded with scepticism by some in tech and media circles. It is unclear, for example, how the company is funding its current growth.
TMTG is planning to list in New York through a merger with blank-check firm Digital World Acquisition (DWAC) and stands to receive $293 million in cash that DWAC holds in a trust, assuming no DWAC shareholder redeems their shares, TMTG said.
Additionally, in December TMTG raised $1 billion committed financing from private investors; that money will not be available until the DWAC deal closes.
However, Digital World's activities have come under scrutiny from the Securities and Exchange Commission and the US Financial Industry Regulatory Authority and the deal is likely months away from closing.