Reichmann was born in Vienna in 1930 to Samuel Reichmann, a wealthy egg merchant, and his wife Renée. His parents were Orthodox Jews from a small town in Hungary, but his father had risen to prominence in Vienna as a successful merchant. Paul was the fifth of six children.
The family escaped the Nazi occupation of Austria unintentionally. They had left the country on the day of Anschluss to visit Samuel's father in Hungary who had suffered a stroke. Abandoning their lives in Vienna, they made their way from Hungary to Paris, where they settled. The Reichmann family fled when France fell to the Germans, eventually making their way to the neutral Moroccan city of Tangier, and the Tangier International Zone.
In Tangier, the family prospered as Samuel became a major currency trader. After the war Paul left home to study Judaism first in Britain and then in Israel, and became a Rabbi. In 1953 he returned to Morocco to become a shirt retailer, and that same year he married Leah Feldman.
Three years later Paul left Morocco to join his elder brother Edward in Canada. Edward had established Olympia Flooring and Tile, a successful flooring and tile company in Montreal. Paul, along with his brothers Albert and Ralph, moved to Toronto to set up a branch of the flooring and tile company in that city.
Unsatisfied with the local builders, Paul Reichmann decided the company would construct its own warehouses and offices. Soon the company was building such facilities for others. In 1964, Olympia and York was founded as a separate building and property development firm.
The firm was soon profitable, and expanded rapidly. It also accepted difficult projects, including the construction of First Canadian Place, Canada's tallest building, in 1976. The company expanded to New York City and Tokyo and by the mid-1980s it was the largest developer in the world, and the Reichmanns were one of the world's richest families.
His success had little impact on Paul Reichmann's lifestyle. He remained very private and unwilling to talk to the press. He retained his strong religious views, and used much of his fortune to support his religion. In Toronto he built a number of schools and synagogues which became the centre of a thriving Orthodox community. Shunning most luxuries, his one personal indulgence was collecting rare and valuable Jewish texts. Pursuant to Jewish law, all of Olympia and York's construction projects halted on the Jewish Sabbath and all holy days.
The company ran into severe trouble in the early 1990s. It was due in part to a general decline in the world economy, but the company was truly brought low by the Canary Wharf project. It was the world's largest property development, but remained half empty. Reichmann had taken the project as a major gamble. He had been impressed by Margaret Thatcher's reforms and obtained a personal promise from her that she would help the project, most importantly by extending the London Underground to reach it.
In Canada, Reichmann's once sterling reputation also began to suffer. In 1985 the company had bought Gulf Canada Resources in a deal that included some $300 million in tax breaks. Many Canadians were infuriated that a massive corporation had been given such a lucrative deal. Toronto Life magazine also published a highly critical article on the Reichmanns. The family took offence at allegations that Samuel Reichmann had aided the Nazis with illegal smuggling operations during the Second World War. The family sued the magazine for an unprecedented $102 million. They were successful, and Toronto Life published a full retraction.
In 1992, as Olympia and York collapsed under some $20 billion in debt, Reichmann lost most of his family fortune.
Despite these setbacks, Reichmann successfully rebuilt a small portion of his empire. This included setting up a partnership with George Soros, Lawrence Tisch and Michael Price, along with investors such as Saudi Prince Al-Waleed, to purchase a controlling stake in Canary Wharf from the banks that made the original construction loans to Reichmann and which had taken control of the development. Reichmann became Chairman of Canary Wharf again and remained so until 2004.
During 2004, a takeover battle began for the Canary Wharf Group in which Reichmann eventually sided with Canadian developer Brascan to attempt a purchase of the company. During this process, he resigned his position on the Board. In March 2005, a consortium of investors led by Morgan Stanley under the banner of Songbird Estates purchased Canary Wharf Group, and Reichmann was therefore no longer involved with Canary Wharf on a day-to-day basis. Reichmann, at the time 75, announced that he intended to retire from business and sold many of his property holdings.
In September 2006, Reichmann announced that he was bored with retirement and that he would be setting up a new $4 billion fund, based in Toronto, with offices in Great Britain and the Netherlands.
Paul Reichmann died at the age of 83 in Toronto on 25 October 2013. His funeral took place Saturday night, 26 October 2013, at the Bais Yaakov Elementary School (15 Saranac Boulevard), in Toronto. He was buried in Jerusalem, in Har Hamenuchot cemetery.