Dorfman died Saturday in New York of cardiogenic shock, a heart condition, according to his family.
Once dubbed the "nation's most prominent stock market tipster," Dorfman was hired by CNBC in 1990 after more than two decades of writing financial columns for the Wall Street Journal, USA Today and other publications. He was also on public TV's "Wall $treet Week With Louis Rukeyser" and CNN's "Moneyline."
Each weekday during the noon hour on CNBC, the raspy-voiced Brooklyn native appeared on camera to offer his "pick of the day," a three-minute stock analysis that frequently included a buy or sell recommendation for a particular company.
In 1994, the Washington Post reported that during an 18-month period, more than 95% of the stocks recommended in the reports dramatically increased in price — by an average of about 13% — usually within five minutes of Dorfman's report. The companies that he knocked quickly dropped in value by about the same percentage.
"There's an audience that tunes in every day … just to watch Dorfman," CNBC Vice President Peter Sturtevant told the Washington Post. "They reach for their telephones and buy or sell based on what they hear."
Dorfman's critics, the paper reported, charged him with reporting inaccurate information given to him by speculators who stood to profit from the rapid movement in the price of stocks discussed on the air, but Dorfman said he always tried to be accurate.
He was working for CNBC and Money magazine in 1996 when Money fired him from his columnist's job for refusing to reveal confidential news sources to his editor. The firing came in the wake of published reports that federal authorities were investigating Dorfman's relationship with a stock promoter.
The stock promoter later pleaded guilty to charges of securities fraud. Dorfman was never formally accused of wrongdoing.
He suffered a mild stroke in 1996 and his contract with CNBC was not renewed.
He later wrote for Financial World magazine, the financial information service Jagnotes.com and the New York Sun. He also blogged for the Huffington Post until last year.
Born in New York City on Oct. 24, 1931, Dorfman worked as a printer before serving a stint in the Army. After working for a number of New York newspapers, he was hired to write the "Heard on the Street" column for the Wall Street Journal in the late 1960s.
He is survived by his wife, Harriet.