Israel concluded an investigation on Monday and said she was likely to have been "unintentionally shot" by an Israeli soldier.
"We welcome Israel’s review of this tragic incident and again underscore the importance of accountability in this case, such as policies and procedures to prevent similar incidents from occurring in the future," US State Department spokesman Ned Price said.
Mr Price said she was an American citizen and "a fearless reporter whose journalism and pursuit of truth earned her the respect of audiences around the world".
"Our thoughts remain with the Abu Akleh family as they grieve this tremendous loss – and with the many others worldwide who brought Shireen and her news reports into their homes for more than two decades," he said.
Mr Price said the US Department of Defence "recently underscored the need to improve its own assessments and practices to ensure civilian harm mitigation and we will continue to share best practices with our military partners and allies around the world".
The Israeli military said troops conducting the raid in Jenin came under heavy fire from all sides and fired back, including towards the area where Abu Akleh was standing.
It said soldiers had not been able to identify her as a journalist.
But footage has showed that Abu Akleh wore a blue flak jacket clearly marked with the word “Press” during the operation.
The military said "there is a high possibility that Abu Akleh was accidentally hit by IDF gunfire that was fired towards suspects identified as armed Palestinian gunmen".
It also said it was possible she was hit by Palestinian gunmen.
Abu Akleh was born in Jerusalem and began working for Al Jazeera in 1997. She regularly reported on-camera from across the Palestinian territories.
In July, Abu Akleh's family demanded an independent investigation into her death during a meeting with US Secretary of State Antony Blinken.
"We are here to demand justice for Shireen," Lina Abu Akleh, the journalist's niece, said outside the State Department building in Washington.
"Nothing short of a US investigation that leads to real accountability is acceptable, and we won’t stop until no other American or Palestinian family endures the same pain we have," she said on Twitter.