In 1961, Halley, alongside his father, Paul-Auguste, and his brother, Paul-Louis, founded the retail group Promodès, where he would spend his entire career.
Following the accidental death of his brother in 2003, Halley became his family's sole representative on Carrefour's management board.
[1] In 2007, after Colony Capital and the Groupe Arnault [fr] acquired a stake in Carrefour, he replaced Luc Vandevelde as head of the supervisory board.
[4] In 2009, according to Challenges, he was the 11th richest French man, with a net worth of 2.769 billion euros.
He oversaw the decision to sell the town hall to finance the burial of electricity networks.