The footage shows a convoy of U.S. vehicles under attack by ISIS fighters.
Members of a SEAL quick reaction force rush in to rescue a small team of American advisers and their Kurdish allies.
About a dozen U.S. special operations forces are seen in the video.
The team was assaulted by more than 100 ISIS fighters who penetrated the front lines with truck bombs and bulldozers.
Keating, 31, was directly hit.
A medevac helicopter, under heavy gunfire, was able to evacuate Keating to a combat hospital in Erbil where he was pronounced dead.
The U.S. military said this fight, lasting for 14 hours and killing 60 ISIS fighters, was the largest ISIS assault in months.
U.S. troops were only present for the first few hours of the battle.
Only two other Americans have suffered combat deaths in Iraq since the U.S. returned to the country in June 2014.
In late March, Marine Staff Sgt. Louis F. Cardin, 27, was killed by ISIS rocket fire on his artillery support base near Makhmour, in northern Iraq.
Last October, Army Master Sgt. Josh Wheeler, 39, was killed in a raid in northern Iraq, which rescued 70 Iraqi hostages taken by ISIS.
Speaking in Stuttgart, Germany, Sec. Carter highlighted the combat risks facing the roughly 5,000 U.S. troops in Iraq.
"It shows you it's a serious fight that we have to wage in Iraq," he said.