From La Plata in Argentina, Mazzacane started racing in 1989 in Karting. His father had been a touring car driver in his own day and Gaston was named after the Argentine touring car star, Gaston Perkins. Gaston proved quite adept and won both regional and national titles in his homeland before finally making the step up to cars in 1992 sponsored by his father's distribution business for Quilmes beer. Initially he drove a Datsun 280ZX in the Argentine touring car series, before switching to single seaters in the highly competetive South American F3 series.
He recorded five wins which gave him the confidence to move to Europe to ply his trade. He initially drove in the Italian Formula 2000 series with RC Motorsport and won the title at his first attempt, before signing a deal to race in the national F3 championship with BVM Racing in 1995.
He had driven one of RC's F3 machines a couple of times in 1994 but the BVM team were not up to the task and Mazzacane finished a dissapointing 17th in the series.
Not wanting to spend another year in F3 he opted to move to F3000 in 1996. He had a brief taste of the formula in 1994 with Autosport Racing but once again his results were unimpressive.
After another poor year in 1997 he switched to the Astromega team but little else changed, with just two points to show for his efforts.
Mazzacane quit F3000 at the end of 1998 to concentrate on finding an F1 drive for the following season and landed a test role with Minardi on the back of sponsorship from Argentina. He also raced in sports prototypes in the International Sportscar Racing Series. Teaming up with Giovanni Lavaggi in the Italian's GLV Brums Ferrari 333SP they contested seven rounds together. They retired at Monza, Brno and the Nurburgring, but they finished the other four, finishing 4th at Barcelona, 6th at Enna, 2nd at Donington, and winning at Magny-Cours. They finished 10th place equal with 51 points each.
Despite average testing performances, Mazzacane's was offered a full race seat for 2000. This was primarily due to part-owner, Telefonica, wanting a South American driver to partner Marc Gene.
"I intend to learn over the first half of the season and then I feel I will have the confidence to perform well," Mazzacane told the press at Minardi's showy car debut at the Guggenheim Museum in Bilbao.
Mazzacane's debut year was average. A broken gearbox at the Melbourne GP was tempered with a 10th place at Brazil. Mazzacane manahed to outqualified teammate Gene at Imola, the first of four times. Germany was a relative high point for Mazzacane. After outqualifying his teammate, Mazzacane ran well and finished 11th on the same lap as the leaders.
In the US Grand Prix he had his geatest moment of glory in F1. Having out-qualified Gené by over half a second in qualifying, he stayed out on wets in the early stages of the race as the track was drying up, and found himself up in 3rd place with reigning World Champion Mikka Hakkinen behind him. For three laps, Gaston kept ahead with an agitated Finn waving his fist, not knowing that Mazzacane was actually in front of him on the road. Then, when Mazzacane went into the pits, he ran over two of his crew members. "I made a big mistake under braking at the second stop and I locked my wheels, running over two guys from my crew," he later told the press. Gaston dropped back and finally retired with engine failure.
Mazzacane finished 11 of the 17 races that year and ranked third in the number of kilometers completed, only behind the two McLaren drivers.
With Minardi changing hands at the end of the year, Gaston had to look elsewhere. Arrows showed interest, despite the fact that they had both Jos Verstappen and Pedro de la Rosa under contract. Gaston had tested for them in the rain at Silverstone, but was probably never in contention for a seat.
However Prost Grand Prix, who had lost several major sponsors after a poor year in 2000, needed a paying driver to help cover the cost of the customer Ferrari engines they had secured to the season. Pedro Diniz had bought a stake in the team, but opted not to drive alongside Alesi.
Gaston was thus signed to drive the new AP04, however Alain Prost put a performance clause in Gaston's contract as, though he wanted Mazzacane's money, he could not afford to mave an uncompetetive driver in the car.
Gaston had to really prove himself, but in Melbourne, he got off to a slow start. Qualifying 20th, ahead of Luciano Burti's Jaguar and Marques' Minardi, he was nonetheless slower than Alonso and over 0.9s behind Alesi. And although the Prost would prove reliable throughout 2001, Gaston didn't even complete the first lap of the Australian GP after brake pedal problems.
By the fourth race rumours were rife that he was about to be dropped and, when Jaguar replaced Burti with de la Rosa after Imola, the Brazilian went to Prost and Mazzacane was out.
Prost folded at the end of the year and a new team run by Tom Walkinshaw and Chris Nickerson bought the assets. This new team, Phoenix, signed Mazzacane to race in 2002 season. However the team was barred from racing and his F1 carrer was over.
He was then linked to rides in both the IRL and FIA F3000 for 2003, Mazzacane appeared to have vanished from the international racing radar until resurfacing at Dale Coyne's Champ Car team in 2004. He made his Champ Car debut in Milwaukee that year, replacing Tarso Marques. He finished seven of his nine starts with the highlight of his year in Toronto where he made up ten positions to finish a career-high sixth.
Currently racing a Passat TRV6 for AS Racing in South American Top Race V6 Touring Car series.