Ladány was born in Budapest in 1914. He initially wanted to become a violinist and trained as such, but in 1936 he entered the Jesuit order. He also went to China that year, living first in Peking and then Shanghai.
After the end of the Chinese civil war in 1949 László Ladány and other Jesuits were forced to flee China, and he settled in Hong Kong. He began publishing China News Analysis in 1953 from the University of Hong Kong, and became well known by China watchers and journalists around the world. Ladány based his assessments and conclusions mainly on readings of official Chinese documents, and was consistently critical of Communist Party rule, earning him the ire of Communist Party supporters abroad.
Ladány, who was variously called a "fanatical anti-Communist" by critics and as "the most exact and consistently correct observer" of mainland Chinese politics by admirers, possessed an uncanny ability to draw meaning out of often cryptic official Chinese documents. Jürgen Domes described him as having attained "unprecedented prestige as a China scholar, [...] the doyen of the international community of observers of contemporary Chinese politics".
Ladány served as the sole editor of China News Analysis from its founding until 1982, when he left the journal to pursue a career as an author.
The sinologist Simon Leys gleaned much information from "the superb China News Analysis, ... published weekly in Hong Kong by the Jesuit scholar Father Laszlo Ladany" while compiling reports that would become the basis of his 1971 book Les Habits neufs du président Mao. In 1975 that book was awarded the Prix Jean Walter, prix d’histoire et de sociologie by the Académie française and in 1978 it was published in English as The Chairman's New Clothes.
In the final edition of China News Analysis for which Ladány served as editor, he compiled a "ten commandments" describing his philosophy on the study and assessment of contemporary Chinese politics:
1. Remember that no one living in a free society ever has a full understanding of life in a regimented society.
2. Look at China through Chinese spectacles; if one looks at is through foreign glasses, one is thereby trying to make sense of Chinese events in terms of our own problems.
3. Learn something about other Communist countries.
4. Study the basic tenets of Marxism.
5. Keep in mind that words and terms do not have the same meaning in a Marxist society as they do elsewhere.
6. Keep your common sense: the Chinese may have the particular characteristics of Chinese, but they are human beings, and therefore have normal reactions of human beings.
7. People are not less important than issues; they are probably more so. A group may adopt the programme of those who oppose it in order to retain power.
8. Do not believe that you know all the answers. China poses more questions than it provides answers.
9. Do not lose your sense of humour. A regimented press is too serious to be taken very seriously.
10. Above all, read the small print!— László Ladány, China News Analysis, Dec 1982
Famine mortality estimate
In the August 10, 1962, issue of China News Analysis, Ladány accurately noted the existence of the massive famine resulting from Mao's Great Leap Forward and offered a "realistic estimate" of 50 million deaths. This was based on letters sent from the Chinese mainland and on refugee reports. Many years later Frank Dikötter was to estimate in his book Mao's Great Famine (2010) a death toll of "at least" 45 million, a close confirmation of Ladány's figure.
- China News Analysis, editor, (1953 - 1982)
- The Communist Party of China and Marxism 1912-85: A Self Portrait. London: C. Hurst & Co. Publishers Ltd., 1988.
- The Law and Legality in China: the testament of a China-watcher, edited by Jürgen Domes and Marie-Luise Näth. London: C. Hurst & Co. Publishers Ltd., 1992.
- "Laszlo Ladany, China Expert, 76", The New York Times, 26 September 1990.
- Law and Legality in China: The Testament of a China-Watcher, by Laszlo Ladany, edited by Jürgen Domes and Marie-Luise Näth. London: C. Hurst & Co. Publishers Ltd., 1992.
- Simon Leys, "The Art of Interpreting Nonexistent Inscriptions Written in Invisible Ink on a Blank Page", The New York Review of Books, 11 October 1990.
- Ian Buruma, "The Man Who Got It Right", The New York Review of Books, 15 August 2013.