At last Decatur organized his celebrated expedition in the ketch Intrepid, and among the eleven officers he selected for that glorious enterprise was Macdonough. At that time Macdonough was still a midshipman. He was tall and very slender, never having been physically strong; but he was, even then, a man for the post of danger.
The ketch set off on the 3d of February from Syracuse and returned on the 19th, having in that time entered the well-guarded harbor of Tripoli by night, burned the Philadelphia at her moorings, and escaped without losing a man. Macdonough was the third man on the Philadelphia's deck, and was especially active in his work of distributing the powder for the ship's destruction in her storerooms aft. No officer in that glorious expedition conducted himself better than Macdonough; and when it is remembered that Decatur commanded it, that James Lawrence was one of his lieutenants, and Charles Morris, who was afterward Captain Hull's first lieutenant in the escape of the Constitution and the capture of the Guerrière, was one of the midshipmen, it will be seen that Macdonough was measured by no common standard.
Macdonough shared in all the glory of those splendid campaigns, and received the thanks and commendations of his superiors, besides promotion. In 1806 he was made first lieutenant of the Siren, one of the smart brigs that had done good service during the Tripolitan war. She was at Gibraltar, where the British navy is always very much in evidence; and Macdonough, the mild and forbearing, soon had a chance of showing the stuff that was in him. One day, while his commanding officer, Captain Smith, was on shore, Macdonough noticed a boat going from a heavy British frigate that lay close to an American merchant vessel. When the boat repassed the Siren, on her way back to the frigate, she carried one more man than she had on leaving the frigate. In those days, if a British captain suspected an American merchant vessel of having a British subject among the crew, it was common enough to seize the man, and when once on board a British ship, it mattered little whether he were American or British, there he had to stay. Macdonough suspected this to be the case, and sent a boat to the brig to ask if a man had been taken and if he were an American. Such was actually reported. Macdonough at once ordered the first cutter lowered, and although she pulled only four oars and the British boat pulled eight, he set off in pursuit. He did not catch up with the British boat until she was directly under the frigate's quarter, and the man in the bow had raised his boat-hook. Suddenly Macdonough reached forward, and, catching hold of the prisoner, who sat in the stern sheets, lifted him bodily into the American boat, and before the British could believe their eyes, was well started on his way back to the Siren.