Answer: His father
When Jack and Gibbs fled the courtroom, Jack thought he had paid the carriage driver to take them to an exit route. Instead, they were brought to King George's palace. King George heard that Jack knew the route to the Fountain of Youth, and wanted him to navigate an expedition to be led by Captain Barbossa, now a privateer employed by the Crown. Jack escaped from the palace and was chased by several guards. When he thought he had successfully eluded them, he found that there was one more standing behind him, aiming a gun at him. Suddenly a shot was heard and the guard fell to the ground, dead. The gunman stepped out of the shadows and Jack greeted him as "Dad". It was Captain Teague, played by Keith Richards reprising his cameo role from the previous "Pirates" flick, "At World's End".