Diniz’s father, Valentim Diniz, founded the company Pão de Açúcar in September 1948. Abilio Diniz began to work for his father at Doceria Pão de Açúcar at the age of 12. In April 1959, the same year he graduated from FGV in Business Administration, he partnered with his father to create the first Pão de Açúcar supermarket store, located on Brigadeiro Luiz Antônio Avenue, in São Paulo. In 1960, after the first store was established, Diniz traveled for four months throughout Europe and the United States to observe the operation of the retail sector abroad. The second Pão de Açúcar location on Maria Antonia Street, downtown São Paulo, was established in 1963. One year later, Pão de Açúcar acquired Quiko and Tip Top supermarkets. During the 60’s and 70’s, Grupo Pão de Açúcar was the first supermarket chain to set up a store in a shopping mall (Iguatemi, in São Paulo), to have a 24-hour pharmacy, and to set up a data processing center.

Diniz studied at Anglo-Latino school and Mackenzie high school. He graduated in 1956 from the School of Business Administration of Fundação Getúlio Vargas. In 1965, Diniz traveled to the United States to study Marketing at Ohio University and Economics at Columbia University, in New York.

Diniz studied the operations of Paris-based Carrefour in 1967 after Luiz Carlos Bresser-Pereira, who worked at Pão de Açúcar, introduced him to Carrefour cofounder Marcel Fournier. Diniz was a co-founder of the Brazilian Association of Supermarkets in 1968. Inspired by the Carrefour hypermarket model, Diniz founded Jumbo, the first hypermarket in Brazil, in Santo André in 1971. In 1976 he acquired Eletroradiobraz, the second largest chain of supermarkets and hypermarkets in Brazil at the time,. The company consisted of eight supermarkets, 26 hypermarkets, 16 stores and a warehouse.

In 1979, Diniz moved away from Pão de Açúcar and became part of the National Monetary Council at the urging of the Minister of Planning, Mario Henrique Simonsen. There, he coordinated the production of economic bulletins.

In 1989, Valentim asked Diniz to take over the leadership of Pão de Açúcar. Valentim remained part of the group’s board of directors. In March 1990 the Collor government implemented an economic plan which put Pão de Açúcar on the verge of bankruptcy. Diniz implemented the practice “cut, concentrate and simplify” and made cuts across the company. He sold the building which had served as the company’s headquarters since 1986 in 1992. The company, which had 626 stores in 1985, was reduced to 262 stores by 1992. However, family conflicts threatened the company. In an agreement signed in November 1993, Diniz was given the majority control of Grupo Pão de Açúcar. His parents received 36.5% of the company shares and his sister, Lucília, held 12% of the company shares. Diniz led Grupo Pão de Açúcar through an IPO in 1997 and it was listed on the New York Stock Exchange. It was the first 100% national controlled company to conduct a global stock issue (in Brazil, the United States and Europe). In 1999, the French group Casino acquired 24.5% of the voting capital of the group for $854 500 million. In 2000, Diniz transitioned the company into Companhia Brasileira de Distribuição, which became one of the largest retail chains in the country.

In December 1989, Diniz was the victim of a sensational political kidnapping, followed by a police rescue. He was confined for six days in a small space under a house, with a duct leading to the kitchen fan as his only source of oxygen.

The kidnapping took place in the morning of the Brazilian presidential elections in Brazil in 1989.

Lamont and Spencer were sentenced to 28 years in prison for their involvement, but were kept in private cells, away from the mass of the prison population. The Canadian press and public started a major movement to secure their release, straining relations between Brazil and Canada. However, two Canadian investigative journalists, Isabel Vincent of The Globe and Mail and Caroline Mallan of the Toronto Star, wrote books concluding that Lamont and Spencer were likely guilty, and they were being treated well by Brazilian authorities. Lamont confessed to involvement in the kidnapping, which was meant to raise money for Sandinista guerrillas, and the two were released and deported to Canada in 1996.

In 2003, Diniz became a member of the Economic and Social Development Council, a group of civil representatives which advise the President of the Republic of Brazil.

In 2004, Diniz released the book Caminhos e Escolhas – O caminho para uma vida mais feliz (Paths and Choices – Smart Choices for a Successful Life), which discusses major moments in his life and the transformations he went through as a result.

In 2005, Diniz sold a large stake to the French company Casino Group for an estimated $860 million and stepped down as CEO, but remained as chairman. In 2009, in one of the most expensive transactions of the Brazilian business history, Grupo Pão de Açúcar bought Casas Bahia from Samuel Klein, giving Abilio control of Pão de Açúcar, Casas Bahia, Ponto Frio and Extra Hipermercados. In 2012, Casino Group took control of Grupo Pão de Açúcar and Diniz no longer had operational functions within the group but remained as chairman.

In 2006, Diniz founded Península Participações, an investment company created to manage the assets of the Diniz family through private and liquid investments. He later became the chairman of the company’s board of directors.

In August 2011, Diniz was notified by the Federal Public Ministry of Brazil to give explanations in a criminal investigation. Diniz’s next move was to then call criminal lawyer Marcio Thomaz Bastos, one of the most well-known criminal lawyers for those who had wealth. At this time, Diniz was president of the board of directors for Pão de Açúcar. During the 2010 elections, the offices of Bastos had helped Diniz pay 5.5 million reais, to congressman Antonio Palocci to help fund the presidential campaign of Dilma Rousseff.

In April 2013, Diniz was elected as chairman of BRF. He helped lead the company through a broad restructuring. The company’s profit went from R$700 million in 2012 to R$2.2 billion in 2014. The company’s market value went from R$37 billion to R$55 billion.

In September 2013, Diniz signed an agreement with his partner Jean-Charles Naouri to leave Grupo Pão de Açúcar. His shares were converted into voting privileges and he resigned from his position as chairman and the position was filled by Naouri.

He changed his focus to Península Participações, which managed more than 10 billion reais in assets by 2014. In April 2015, Diniz announced he was wrapping up talks to raise his 5.07 percent stake in Carrefour and that he had shareholder support to take a seat on the board of the supermarket. Through Península Participações, Diniz acquired 10% of the shares of Carrefour Brazil. Península Participações continued to acquire shares of Carrefour, and by March 2016, it was the third largest global shareholder of the Carrefour chain. In 2017, it had 11.46% of the shares of Carrefour Brasil and 7.7% of Carrefour. Diniz serves on the group’s board of directors.

In 2015, journalist Cristiane Correa wrote the book Abilio – Determinado, Ambicioso, Polêmico (Determined, Ambitious, and Controversial), released by publisher Sextante, which details his life from childhood to becoming one of the biggest businessmen of Brazil. The book discussed Diniz’s departure from Grupo Pão de Açúcar and his career after the departure.

In October 2016, Diniz launched his second book, Novos Caminhos, Novas Escolhas (New Paths, New Choices), released by publisher Objetiva (Companhia das Letras Group), which discussed the transitions in his life over the previous 12 years. In March 2017 the French version of the book was released, and later an English version was sold in the American market.