Ramírez was born in Mexico City, the third of eight children. He studied mechanical engineering at the National Autonomous University of Mexico (UNAM) but left in 1960 to follow his close friend Ricardo Rodríguez to Europe, where the young Mexican driver was beginning his international racing career. Ramírez found work as an apprentice mechanic with Scuderia Ferrari for two years.
When Rodríguez was killed in a crash during the 1962 Mexican Grand Prix, Ramírez remained in Europe and took positions at Maserati and subsequently Lamborghini, where he worked on the early line of high-performance road cars. In 1964 he moved to England to work for Ford on the GT40 programme, and in 1966 joined Dan Gurney's All American Racers team.
Through the 1960s and 1970s Ramírez worked for a succession of Formula One teams, accumulating wide experience across the paddock. His employers during this period included Dan Gurney's Eagle, Ken Tyrrell's Tyrrell operation — where Tyrrell advised him to keep a diary of his time in the sport — and the Fittipaldi Copersucar team operated by Wilson and Emerson Fittipaldi. He also worked for Shadow and ATS, and for Theodore Racing.
In addition to Formula One, Ramírez was part of the JW Automotive Engineering Porsche sportscar operation that won the 1971 World Sportscar Championship, with Pedro Rodríguez and Jackie Oliver taking the Drivers' title.
In December 1983 Ramírez joined McLaren as Team Coordinator, a role he would hold for the next 17 years. The timing placed him at the centre of one of the most successful and fractious periods in Formula One history. He developed close friendships with the team's drivers, including Alain Prost, Ayrton Senna, David Coulthard, and Mika Häkkinen, and was a trusted figure in a team renowned for its internal demands.
Over his McLaren tenure Ramírez participated in 479 Formula One Grands Prix and was part of 116 victories. The team won seven Constructors' Championships during his time — 1984, 1985, 1988, 1989, 1990, 1991, and 1998 — and five Drivers' Championships: Jackie Stewart once prior (counted in his cumulative record), plus Niki Lauda (1984), Alain Prost (1985, 1986, 1989), Ayrton Senna (1988, 1990, 1991), and Mika Häkkinen (1998, 1999).
Ramírez retired from the sport after the 2001 United States Grand Prix, which was also Mika Häkkinen's final Formula One race win. As a leaving gift, Coulthard and Häkkinen presented him with a Harley-Davidson Road King at the 2001 Hungarian Grand Prix. McLaren team principal Ron Dennis counselled Ramírez against writing his memoirs on the grounds that no one would be interested; Ramírez later noted that Dennis's real concern was preventing disclosure of the team's internal workings.
In 2005 Ramírez published his autobiography, Jo Ramirez: Memoirs of a Racing Man. Fluent in Spanish, English, Italian, and Portuguese, he subsequently wrote forewords for several books including Los Hermanos Rodríguez (2006), The Brothers Rodríguez (2009), and La Carrera Panamericana: "The World's Greatest Road Race!" (2008). He maintained a regular column in the Mexican newspaper Reforma during Formula One seasons.
Ramírez became active in the historic Carrera Panamericana road race following his retirement, competing in a Volvo P-1800 under the Escuderia Telmex banner. He achieved fourth place in the A+ Historic category in 2010 and a podium third place in the A+ Historic 2,000 cc class in 2012.
He was a visible mentor to a generation of Mexican motorsport talent, supporting drivers including Adrián Fernández, Salvador Durán, Sergio Pérez, and Esteban Gutiérrez during their careers. He is a member of the Scuderia Rodríguez and a member of Mexico's Hall of Fame of Motorsport.
Jo Ramírez's career spanned more than four decades, eight Formula One teams, and some of the sport's defining moments — from the rear-engined revolution of the 1960s through the turbocharged era and the Prost-Senna years to the late-1990s McLaren renaissance. As a Mexican national who reached the organisational heart of the most successful Formula One team of the modern era, he became an important figure for Latin American motorsport identity, and his published memoirs offer a rare ground-level account of Formula One's inner workings across its most intensely competitive period.