He pioneered the construction of super tankers in Japan, founded Exportadora de Sal, SA in Mexico and developed it as the largest salt company in the world, built a model community in association with the Jari project, which he pioneered, on the Amazon River in Brazil to produce pulp paper, and had numerous hotels around the world.

Though he was one of the wealthiest tycoons of his day, with operations spanning 23 countries, Ludwig remained completely obscure due to his reclusive lifestyle.

[1] His grandfather's brother, Lancaster Columbus Ludwig (1855–1954), served as a captain on a passage steamer from South Haven to Chicago for many decades.

[1] He left school at the end of eighth grade to work in various shipping-related jobs on Lake Michigan and in Texas, directly learning such trades as machinist, marine engineer, and ship handler.

In the 1940s, one of his shipyards in Virginia developed a method to use welding instead of riveting, which saved time during World War II, when there was huge demand for new ships.

[1] Ludwig diversified into a wide range of holdings: an oil refinery, banking, cattle ranching, insurance, and real estate.

[6] In 1954, on a trip to Baja California Sur, Ludwig founded Exportadora de Sal S.A., which became the "Largest Salt Company in the World", at the Guerrero Negro lagoon.

In 1973, with rumors that the Mexican Government would nationalize the company, Ludwig sold his interest in Exportadora de Sal, SA to Mitsubishi.

The New York Times reported that an auction of Citricos de Chiriqui, SA failed to attract any bidders; the minimum asking price was $13.9 million.

A brutal military dictatorship had toppled the progressive Goulart government in a 1964 coup, with US backing, and US investment was encouraged by the conservative Brazilian generals in power.

The site was downriver from American Henry Ford's failed massive project to produce rubber, for which he built a workers' city in the jungle, Fordlandia.

But in 1978 he had a plant shipped by sea in two parts from where it was fabricated in Japan: these were "two behemoths 70 meters high, unique in the history of the merchant navy.

New Finnish machinery and technology has drastically reduced the required labor force and, as Le Monde noted, machines neither strike nor go to the brothels of Beiradao.

The government cooperated in approving a hydropower project which Ludwig had sought, and even the slum was improved, as well as renamed to Laranjal do Jari.

Believing Patricia might at some later time try to challenge the terms of his will and claim part of his estate, Daniel Ludwig had blood samples frozen in the 1970s that could be used for genetic testing if ever necessary.

Katherine Jones, Patricia's aunt, claimed that everyone in the family thought that Patricia's father was James Sullivan, a sales rep who died in a car accident in 1939 [14][15] Several months after his divorce, Ludwig married Gertrude Virginia "Ginger" Higgins (January 13, 1897 – April 8, 1993), a widow with three children from a previous marriage.