Hamill worked his way up the New York tabloids as a reporter, columnist and editor, and covered historic moments from Robert F. Kennedy's assassination to the terrorist attacks on Sept. 11. Fellow veteran journalists and leaders expressed their condolences throughout the day.
"Pete was truly one of the good guys," younger brother Denis Hamill, a Daily Beast columnist, told New York ABC station WABC.
Pete Hamill was born in 1935 in Park Slope, Brooklyn, to Irish immigrants. The oldest of seven children, he dropped out of high school and worked in the Brooklyn Navy Yard before going to art school.
After a stint in the U.S. Navy ended in 1957, Hamill worked as an art director for a local Greek paper and frequently wrote letters to the New York Post. Hamill's correspondence attracted the attention of the paper's editor, Jimmy Wechsler, who invited the 25-year-old to a meeting.
"While we talked, he smoked cigarettes and sipped coffee. Near the end of our chat, he leaned back in his chair and put his hands behind his head. 'Have you ever thought about becoming a newspaperman?'" Hamill wrote in his memoir.
Hamill joined the New York Post in 1960 and covered a variety of stories from local crime to national politics. Over the next three decades, he worked at several New York papers, including the Daily News, New York Herald Tribune, the Village Voice and New York Newsday.
The New York Press Club, a nonprofit association for New York journalists, said in a statement that New Yorkers eagerly read Hamill's articles and it had an impact on all of their lives.
"As a columnist, Pete was one of a select few whose opinions were highly anticipated by the public as events unfolded and daily newspapers were delivered. Government officials, too, awaited his take on a news story, sometimes in order to formulate policy," the group said in a statement.
New York Times columnist Jim Dwyer tweeted that Hamill's words were critical in amplifying New York issues during the '70s, "like the patriots in Casablanca drowning out the Nazis with La Marseillaise."
"The goodness of his generous heart never ran low. Thanks for all of it," Dwyer tweeted.
It was also during this time that Hamill battled his demons. In his memoir, "A Drinking Life," he opened up about his years of alcoholism during the 1960s and early '70s and its effect on his relationships and work.
Hamill said he had his last drink on New Year's Eve 1972.
"I think the one thing you find out when you stop drinking is just how much time you have," he said in a 1994 interview on C-SPAN. "You have time to read. You have time to listen to music, not just have music as background on a jukebox in a bar, but to listen to it."
In 1993, he was hired as the editor in chief of the New York Post in 1993, however, a public dispute between the editorial staff and owner Abe Hirschfeld led to him leaving a month later. In 1997, he was hired as the editor of the Daily News, but he resigned eight months later.
Hamill continued to write columns for the Daily News in the subsequent years, including one published Sept. 12, 2001 that reflected on the World Trade Center's destruction.
In addition to his journalism work, Hamill also authored several nonfiction and fiction books, including "Snow in August," "Forever," "Why Sinatra Matters" and "Downtown: My Manhattan." While the topics and genres of those works were eclectic, many shared a similar backdrop: New York City.
Hamill's career was featured in an HBO documentary "Deadline Artists" along with fellow New York columnist Jimmy Breslin.
Gov. Andrew Cuomo called Hamill a quintessential New Yorker in a statement.
"I learned much from him and he inspired me. Pete's death is going to leave a hole in the heart of New Yorkers," he said in a statement.
Hamill's first marriage, to Ramona Negron, ended in divorce in 1970, and he retained primary custody of his two daughters, Adrienne and Deirdre. In 1986, Hamill married the Japanese journalist Fukiko Aoki, whom he met while touring Japan to promote his collection of short stories, "Tokyo Sketches."
Hamill is survived by Aoki, his two daughters, a grandson and four of his siblings.