After the 1982 murder of his daughter Dominique, an actress, he began to write about the interaction of wealth and high society with the judicial system.

[3][4] His maternal grandfather, Dominick Francis Burns (1857–1940), was a successful grocer, who, in 1919, co-founded the Park Street Trust Company, a neighborhood savings bank.

[5] Although his Irish Catholic family was affluent, Dunne recalled feeling like an outsider in the predominantly WASP West Hartford suburb where he grew up.

Dunne served in World War II and received the Bronze Star for heroism during the Battle of Metz.

The brothers wrote a column for The Saturday Evening Post and they also collaborated on the production of The Panic in Needle Park.

Dunne's article "Justice: A Father's Account of the Trial of his Daughter's Killer" ran in the March 1984 issue of Vanity Fair.

He covered the famous trials of O. J. Simpson, Claus von Bülow, Michael Skakel, William Kennedy Smith, and the Menendez brothers.

The Library of America selected Dunne's account of the Menendez trial, Nightmare on Elm Drive, for inclusion in its two-century retrospective of American true crime writing, published in 2008.

"[10] In 2008, at age 82, Dunne traveled from New York to Las Vegas to cover O. J. Simpson's trial on charges of kidnapping and armed robbery for Vanity Fair.

[13] He died on August 26, 2009, at his home in Manhattan[14] and was buried at Cove Cemetery, in the shadow of Gillette Castle in Hadlyme, Connecticut.

He donated these papers to the Dolph Briscoe Center for American History at the University of Texas at Austin,[20] and Robert Hofler detailed them in his 2017 biography Money, Murder, and Dominick Dunne: A Life in Several Acts.