Deputy US Ambassador to the UN Robert Wood said, "We do not support this resolution's call for an unsustainable ceasefire that will only plant the seeds for the next war."
The United States and Israel oppose a ceasefire, saying it would only benefit Hamas, which Israel has vowed to annihilate.
Palestinian UN envoy Riyad Mansour told the council the vote means that millions of Palestinian lives hang in the balance.
Ezzat El-Reshiq, a member of Hamas' political bureau, condemned the US veto as inhumane.
Israel's UN Ambassador Gilad Erdan said in a statement, "A ceasefire will be possible only with the return of all the hostages and the destruction of Hamas."