Gaetjens joined Etoile Haïtienne at the age of fourteen and won two Ligue Haïtienne championships in 1942 and 1944. In his first championship appearance, at the age of eighteen, came against longer established Racing Club Haïtien, another club in Port-au-Prince. Down 3–0 at halftime and a heckling goalkeeper directed at Gaetjens after each goal scored, "Ti-Joe" urged his teammates to hold its defense to allow no more goals. Less than ten minutes after Racing's last goal, Gaetjens rebounded and scored to break the shutout. At the 53rd minute, Fritz Joseph scored. With seven minutes remaining, Frérot Rouzier scored the tying goal equalizing the match at 3–3. At the final minutes of regulation, a defiant Gaetjens kept on the offense, breaking the tie at 3–4, which ended up being the game-winner. To this day, Racing Club Haïtien refuses to play matches on the "Jeudi Saint" (Holy Thursday); the day of washing of the feet. During his tenure with the club, he became known for his goal-scoring headers.