Eli Broad, who has died in Los Angeles at the age of 87, is the only person to have founded Fortune 500 companies in two different industries — the construction and insurance businesses through which he amassed a fortune of $6.9bn, according to Forbes.

As his wealth grew he devoted more of his time and resources to philanthropy, and the name of Broad (pronounced Brode) has adorned schools and college programmes, medical facilities and research, awards and bursaries, and mighty contributions to the visual and performing arts. A life-long Democrat, Broad believed in the power of philanthropy and culture to change society: in 2010 he made a commitment through the Giving Pledge to donate 75 per cent of his wealth. The scale of his contributions has dramatically reshaped the cultural life of Los Angeles.

Broad was born in the Bronx in 1933 in very modest circumstances. His family moved to Detroit, and after a hardscrabble adolescence working a range of menial and manual jobs, he studied accounting at Michigan State University. There he met Edythe Lawson and their marriage in 1954 — he 21, she just 18 — was the start of a partnership that lasted until his death. The couple have two sons, Gary and Jeffrey.

Broad’s first business ventures were in the construction of small affordable homes in the Detroit suburbs. In 1963 Broad moved the company, Kaufman & Broad (later KB Home), to Los Angeles; in 1969 it was the first homebuilder listed on the New York Stock Exchange. His move into insurance created SunAmerica, a life insurance company which he sold to AIG for $17.8bn in 1998. The following year, Broad decided to concentrate full time on his philanthropic interests.

The couple set up several charitable foundations, which between them have endowments of more than $2.5bn. Education was an early focus, with programmes for Los Angeles’ public schools to improve the circumstances of students of lower income families and students of colour. There were college scholarships and, for a time, a $1m Broad Prize for Urban Education.

Among other universities Broad’s alma mater at Michigan State was a substantial beneficiary, with a $25m grant to the Broad College of Business, $20m to create an MBA programme, more than $25m for an art museum and more. Across the country, Broad foundations have also contributed hundreds of millions of dollars to medical research and development, focusing mainly on genomics.

But it was probably to the field of the arts that Broad devoted most of his time and energy. Spurred first by Edythe’s interest, the Broads purchased thousands of works, mostly of contemporary art, amassing a Midas-like personal collection that remains one of the country’s finest. The Broad Art Foundation was formed in 1984 to share it with the wider public, and in 2015 the couple opened their most visible achievement — a vast gleaming $140m public museum on Grand Avenue to house their collections, free to all visitors. It is called, quite simply, The Broad.

As a board member and large-scale donor, Broad helped direct the fortunes of a string of important art institutions. He was the founding chairman of Los Angeles’ Museum of Contemporary Art, acquiring important collections, and a trustee of the Los Angeles County Museum of Art. Los Angeles Opera and a performing arts centre at Santa Monica College were also richly endowed. The Walt Disney Concert Hall in downtown LA counted Broad among its leading donors.

Broad prided himself on having achieved success through unorthodox and imaginative strategies, and his 2012 bestseller The Art Of Being Unreasonable: Lessons in Unconventional Thinking set out his credo in business and leadership — as well as what he termed “venture philanthropy”. However, many who worked with him in the arts experienced the other side of this vaunted “unreasonableness”. One commentator claimed his largesse came with “more strings than a marionette” and, by the time he stepped back from his philanthropic work in 2017, Broad’s controlling manner had often put him at odds with individuals and institutions alike.

Nevertheless, voices around America and the world have united in paying tribute to Broad’s exceptional vision and generosity — as well as his unwavering belief in the power of giving and of culture. In a CBS interview in 2011, he said: “Civilisations are not remembered by their business people, their bankers or lawyers. They’re remembered by the arts.”