The three-month delay came Wednesday after defense lawyers asked for more time to go over the prosecution’s evidence.
Chief Special Warfare Operator Edward Gallagher has pleaded not guilty to charges stemming from a 2017 deployment to Iraq.
Prosecutors say he killed a teenage Islamic State fighter under his care and then held his re-enlistment ceremony with the corpse.
They also accuse Gallagher of shooting two civilians in Iraq and firing inadvertently into crowds.
Defense attorney Phil Stackhouse said his team has received more than 1,000 pages of material from the prosecution since the end of January.
The trial has been reset for May 28.