[3] Marquez began to box professionally on August 20, 1966, when he beat Alberto Jorge, who was also making his debut, by a four round decision at the Hiram Bithorn Stadium in San Juan.
Marquez's next bout was against Carlos' brother, the future WBA world welterweight champion Angel Espada.
Only three days after his rematch with Jorge, Marquez followed by fighting the far more experienced, 10-5-5 Jose Colon, at the Cancha Pepin Cestero in the northern Puerto Rican city of Bayamon.
Josue Marquez and Jose Colon fought a rematch on April 29, 1968, at the Hiram Bithorn Stadium in San Juan.
Marquez had a lay-off of almost one year after the Torres rematch, but he returned with a win, on July 5, 1969, over previously undefeated (6-0-1) Joe Cartwright by a fifth round technical knockout in San Juan.
Keeping a busy schedule, Marquez faced Eddie Linder, a fighter with a 25-4-6 record, on August 9, barely one month and four days after the Cartwright knockout.
Having returned from Italy to Puerto Rico, Marquez boxed Rocky Orengo only 12 days after the Salami bout, on April 30, 1970.
Immediately following the fight with Velazquez, Marquez returned to Italy for a rematch against Giampiero Salami, on June 26 at Ancona.
Three months later, Marquez returned to the boxing ring, facing fellow Puerto Rican contender Hector Matta, who was 9-3.
After the Penzo bout, Marquez was allowed to challenge for the vacant Puerto Rican national Lightweight championship.
His rival, Victor Ortiz (not to be confused with the latter world champion boxer and actor of the same name) was 11-2, when he and Marquez faced off on June 20, 1971 in San Juan.
[8] On his next fight, Marquez would face his biggest test until that time, up and coming Puerto Rican prospect and future WBC Lightweight champion of the world, Esteban De Jesus, who was undefeated and untied in 20 bouts.
Marquez then met a debutant boxer, Radames Checo, in a mismatch held on July 28 at Caguas, Puerto Rico.
Held at the Roberto Clemente Coliseum in San Juan, this was the first world title fight staged at that venue.
According to boxing magazine The Ring, Marquez landed a short left hook in round three that dropped the champion, but the fall was scored a slip by the referee, Venezuela's Juan Carlos Tapia.
Marquez boxed future Wilfred Benítez world title challenger Emiliano Villa, by then 13-1, at Barranquilla, Colombia, on July 7 of that year, losing a ten round decision, then awaited almost one year outside the professional boxing ring before coming back, after he promptly lost to another one of Cervantes' world title challengers, the 16-3-2 Adriano Marrero of the Dominican Republic, by a ten round decision at the Roberto Clemente Coliseum in San Juan on June 28, 1975.
One month and a half later, he was back in Colombia, to face 15-2-2 prospect, Miguel Betruz, whom Marquez outpointed over ten rounds at a bullring in Cartagena, on August 16, as part of the card that featured the then WBC recognized world Middleweight champion Rodrigo Valdez retain his belt with a 15 round decision over Rudy Robles.
The pair had a rematch on April 17, 1976, this time at the Roberto Clemente Coliseum, where they fought to a ten round draw (tie).
[13] The win against Marrero turned out to be the last victory of note Marquez achieved in his professional boxing career, since he only fought twice more: first, against a boxer with an 0-3 record, Rolando Garcia, knocked out in four rounds on March 17, 1977 at the Roberto Clemente Coliseum.