Turgut initially worked as a sheppard for a local family of landowners, the Kaya family and was Muslim seaman of Greek descent. He was born in a village near Bodrum, on the Aegean coast of Asia Minor. He was captured and taken prisoner by the corsairs in his youth and had converted to Islam. He was born in the sub-district called Saravalos in the western tip of Bodrum peninsula (which is called Turgutreis in his honour today) and most probably in the Karabağ village on the Aegean coast of Asia Minor. At the age of 12 he was noticed by an Ottoman army commander for his extraordinary talent in using spears and arrows and was recruited by him. Under his support the young Turgut became a skilled sailor, an outstanding gunner, and was trained as a cannoneer and master of siege artillery, a skill which would play an important role in Turgut's future success and reputation as a superb naval tactician. The Ottoman Turkish governor eventually carried Turgut off to Egypt in 1517, where he participated in the Ottoman conquest of Egypt as a cannoneer. He further improved his skills in this field during his presence in Cairo. Following the death of his master, Turgut went to Alexandria and began his career as a sailor after joining the fleet of Sinan Reis. He immediately became one of the favourite crewmen of the famous corsair due to his success in hitting enemy vessels with cannons. Turgut soon mastered the skills of seamanship and became the captain of a brigantine, while given 1/4 of its ownership. After several successful campaigns, he became the sole owner of the brigantine. Turgut later became the captain and owner of a galliot, and arming it with the most advanced cannons of that period, he started to operate in the Eastern Mediterranean, especially targeting the shipping routes between Venice and the Aegean islands belonging to the Repubblica Serenissima.
In 1520 he joined the fleet of Hayreddin Barbarossa, who would become his protector and best friend. Turgut was soon promoted to the rank of chief lieutenant by Barbarossa and was given the command of 12 galliots. In 1526 Turgut Reis captured the fortress of Capo Passero in Sicily. Between 1526 and 1533 he landed several times at the ports of the Kingdom of Sicily and the Kingdom of Naples, while intercepting the ships which sailed between Spain and Italy, capturing many of them. In May 1533, commanding four fustas and 18 barques, Turgut Reis captured two Venetian galleys near the island of Aegina.
In June and July 1538 he accompanied Barbarossa on his pursuit of Andrea Doria in the Adriatic Sea, while capturing several fortresses on the coasts of Albania as well as the Gulf of Preveza and the island of Lefkada. In August 1538 Turgut Reis captured Candia in Crete as well as several other Venetian possessions in the Aegean Sea.In September 1538, with 20 galleys and 10 galliots, Turgut Reis commanded the center-rear wing of the Ottoman fleet that defeated the Holy League under the command of Andrea Doria at the Battle of Preveza. During the battle, with two of his galliots, he captured the Papal galley under the command of Giambattista Dovizi, the knight who was also the abbot of Bibbiena, taking him and his crew as prisoners.
In 1539, commanding 36 galleys and galliots, Turgut Reis recaptured Castelnuovo from the Venetians, who had taken the city back from the Ottomans. During the combat he sank two Venetian galleys and captured three others. Still in 1539, while landing on Corfu, he encountered 12 Venetian galleys under the command of Francesco Pasqualigo and captured the galley of Antonio da Canal. He later landed at Crete and fought against the Venetian cavalry forces under the command of Antonio Calbo.