He was the Grand Admiral (Kapudan Pasha) in command of the Ottoman fleet at the Battle of Lepanto, where he was killed in action.

[6] He was reportedly a very ascetic Sufi man, wearing only "coarse woolen clothes" and paying many visits to the tombs of saints in the City of the Dead necropolis in Cairo.

Some believe that he may have been encouraged by the Holy League's smaller numbers and underestimated the Christians, while others believe he may have feared displeasing the Sultan who had previously commanded him to engage the enemy.

[11][13] This, and the capture of the Banner of the Caliphs by La Real, led to a collapse in Turkish morale, greatly contributing to their rout in the battle.

Author Oliver Warren in the book Great Sea Battles describes the capture and death of Ali Pasha; "The climax came when Don John gave the order to board; once, twice, parties were driven back, but at last they carried the Turkish poop [aft deck].

There Ali Pasha, already wounded in the head by a ball from an arquebus [long gun], tried to buy his life with a promise of treasure.

The Ottoman standard, a sacred emblem inscribed with the name of Allah twenty-nine thousand times and never before lost in battle, was lowered from the maintop."