On Jan 6, 1942, The "All American" 31^st infantry regiment (consisting of about 1600 men) was 1 of 4 regiments in a line of resistance set to oppose the Japanese Army’s approach to the Bataan peninsula. The mission of the 31st was to delay the Japanese Army at a strategic intersection called Layac Junction. The delay, would buy time for the rest of General MacArthur’s Army to prepare defensive positions.

The Japanese army had air supremacy as well as more and larger cannons. For most of the day, the 31^st endured a 8 hour artillery attack that Jim O’Donovan described as:

“it was a greater concentration of artillery fire than during the Meuse-Argonne Campaign of 1917-18 wherein the Allied field artillery pieces were lined up ‘hub to hub’ “. 

Jim, Now in the heat of battle was no doubt thinking of his dad, a decorated artilleryman in the Meuse-Argonne Campaign of WW1.

The artillery barrage was followed by probing enemy patrols in the sector of B Company of the 2^nd battalion. These patrols were a prelude to a general infantry attack , however B Company fled from the battlefield , despite having no losses. The reserve unit, company A, was unable to restore the line and seems to have ran off with B Company.

With the defensive line broken and confidence in B Company lost, the regimental commander, General Steel, ordered L Company, with Major O’Donovan to counterattack the Japanese and re-establish the defensive line at Layac Junction. One account in the book "31st Infantry Regiment" states:

Company L, accompanied by the 3rd battalion's executive officer, Major James J O'Donovan, displayed aggressiveness and confidence, advancing by bounds from the bivouac area... (they) endured almost constant shelling from Japanese mortars and artillery, L Company dashed forward 30 or 40 paces at a time, hitting the ground as shells slammed in around them, then rushing forward again before the dust settled.

Another Book, "Bataan Our Last ditch" describes the major as follows:

Major James J O'Donovan, Battalion executive officer, walked with L Company and lent his colorful presence to the attack. He waved a .45 caliber pistol in the air, carried a Smith and Wesson .38 on one hip, and sported another .45 in the center of his back.

In a personal letter written to Jim's wife Evelyn after the war, Sergeant Abie Abraham recollected:

On the second day at Layac, I was talking with him, all at once a Jap plane comes over on a strafing run, I lit for the foxhole. The major kept glancing toward the bridge to see what the Japs were up to. I yelled “Damn it Major, get your fanny into a foxhole”. He yells “there’s not a bullet that has my name on it”

The mission was a success, L Company managed to restore the line and hold it. For his efforts at Layac Junction, Major O’ Donovan earned the Silver Star Citation, which follows: