In 1986, the firm of Björgólfur Thor's Father Björgólfur Guðmundsson, Hafskip, became embroiled in a financial scandal and was bankrupted; the scandal may have arisen from the efforts of Hafskip's main competitor Eimskip and its allied political party, the Independence Party, to reduce competition, and the events had a considerable effect on the young Björgólfur Thor. At times he has presented his subsequent Business activities as an effort to regain his and his father's reputations and pay their opponents back. Graduating from the prestigious Commercial College of Iceland in 1987, he followed in the footsteps of some of his siblings and moved to the USA, in a move he has portrayed as an attempt to escape an Iceland where he felt an outsider. He began higher education at the University of California, San Diego, later transferring to the Leonard N Stern School of Business at New York University, graduating with a B.S. in Marketing in 1991.
In 1991, Björgólfur Thor went to Russia along with his Father and a friend, Magnús Þorsteinsson. The Icelandic businessmen, together with Russian partners, founded the bottling company Baltic Bottling Plant, which they sold to Pepsi. Next they founded a brewing company, originally called ООО "Торговый дом "РОСА" it was registered in March 1995 and changed its name to Bravo OOO in February 1996. It further changed its name to Bravo International OOO in August 1996 and Bravo International JSC in December 1997. The founders of Bravo were six companies registered in Limassol, Cyprus. Björgólfur Thor was President of all of them. Bravo Brewery became a success producing the premium beer Botchkarov. The company became the fastest growing brewery in Russia. Heineken bought the brewery for $400m in 2002.
Björgólfur Thor's ventures in Russia raised suspicion. An article in The Guardian wondered where Björgólfur Thor Björgólfsson's money came from and noted that in the 1990s the men "were not only ploughing money into the country but doing it in the city regarded as the Russian mafia capital. That investment was being made in the drinks sector, seen by the mafia as the industry of choice." Similar concerns were raised by Die Welt. Competitors in the Saint Petersburg brewing market faced problems. For instance, Ilya Weismann, deputy Director of competing beverage company Baltic, was assassinated on 10 January 2000. Later Baltic Director general Aslanbek Chochiev was also assassinated. One competing Saint Petersburg brewery burned to the ground.
Late in 2002, Björgólfur Thor and Björgólfur Guðmundsson's holding company Samson ehf. gained a 45% controlling share of Landsbanki, Iceland's second largest bank, for about ISK12m in a controversial privatization. The board was announced in February 2003, with the chairman being Björgólfur Thor's Father. Landsbanki was declared to be acting contrary to the interests of the United Kingdom and placed on a watchlist usually used for the blocking of funds to terrorist organizations by the British government after bankruptcy in October 2008.
Björgólfur Thor Björgólfsson is the inspiration for the main character of Bjarni Harðarson's satirical novel about the 2008–11 Icelandic financial crisis, Sigurðar saga fóts: Íslensk riddarasaga, where his counterpart is the main character, Sigurður frits ('fótur') Bjarnhéðinsson. He is also the inspiration for the main character of Bjarni Bjarnason's novel Mannorð ('reputation'), Starkaður Leví, who pays for the identity (and the life) of a well respected Writer.
Two days after the publication of the Icelandic government report on the financial crisis on 12 April 2010, Björgólfur Thor Björgólfsson issued a public apology for his role in the crisis in the Icelandic newspaper Fréttablaðið, including the statement:
Björgólfur Thor and his great-grandfather Thor Jensen are the subject of the 2011 documentary film Thors saga by Ulla Boje Rasmussen.
In December 2013, the website "The Automatic Earth" reported:
Björgólfur was the first Icelander to join Forbes magazine's list of the world's richest people in 2005; has been declared "Iceland's first billionaire"; and was ranked as the 249th-richest person in the world by Forbes magazine in 2007—up from 350th the previous year—with a net worth of $3.5 billion. In 2007 the Sunday Times’ Sunday Times Rich List put his net worth at £2,000 million. However, following the financial crisis of 2007–2010, Björgólfur's net worth had declined to $1 billion by March 2009. He worked out a complex deal with his creditors to pay off his debts while holding on to his key Investments and on March 20, 2017 Forbes estimated his net worth at $1.81 billion. He published an autobiography in 2014.