[4] Daly and his fellow Irish volunteers would eventually be placed in the Connolly Column, part of the Lincoln Battalion of the XV International Brigade and saw action beginning in 1937.

Because of his previous experience in both the Irish civil war and as part of the British army, Daly was used as an officer, rising quickly through the ranks, becoming a Captain after the Battle of Brunete.

As part of their orders, they were commanded on 25 August to capture Purburrel Hill, a height south of the town, on which 500 Rebel troops were entrenched behind barbed wire and concrete pill-boxes,[6] fortified with input from German advisors.

Daly was taken away for aid while his second in command, Paddy O'Daire took charge[7][8] refusing the orders of his superior, Lieutenant Colonel Vladimir Ćopić, to continue the suicidal attack, keeping his men dug in on the exposed hillside until nightfall and safe withdrawal.

[6] On 26 August O'Daire, this time supported by the XV International Brigade's anti-tank battery, succeeded in breaking the enemy lines,[6] leading to the capture of 300 troops.