During the subsequent Battle of Heartbreak Ridge, he voluntarily stayed behind to cover his unit's withdrawal in the face of an intense attack by North Korean forces.

He briefly considered declaring himself a conscientious objector, as his Christian faith made him unsure of killing others but decided against this idea.

With the help of artillery, mortar, and heavy machine gun support, the platoon easily held off a series of probing assaults which began in the mid-afternoon.

With North Korean artillery striking close by and ammunition running low, the platoon caught in cross fire in the rice paddies received permission to withdraw and rejoin the main body of the company as quickly as possible.

As some of his comrades watched from their new position further down the ridge, Pililaʻau threw rocks at the attackers before charging at them, wielding his trench knife with one hand and punching with the other.

[4] In January 2000 in New Orleans, the United States Navy christened a Military Sealift Command cargo ship, the USNS Pililaau (T-AKR-304), in Pililaʻau's honor.

Also named for Pililaʻau are a live-fire range at Makua Military Reservation, a park in his hometown of Wai'anae, and the Pililaau Army Recreation Center.

Pililaau fired his automatic weapon into the ranks of the assailants, threw all his grenades and, with ammunition exhausted, closed with the foe in hand-to-hand combat, courageously fighting with his trench knife and bare fists until finally overcome and mortally wounded.

His heroic devotion to duty, indomitable fighting spirit, and gallant self-sacrifice reflect the highest credit upon himself, the infantry, and the U.S.