Lillian Ross, the ever-watchful New Yorker reporter whose close narrative style defined a memorable and influential 70-year career, including a revealing portrait of Ernest Hemingway, a classic Hollywood expose and a confession to an adulterous affair, has died at age 99.

Ross died early Wednesday at Lenox Hill Hospital after suffering a stroke, New Yorker articles editor Susan Morrison said on Wednesday. In an email statement to The Associated Press, New Yorker editor David Remnick called Ross a groundbreaking writer.

“Lillian would knock my block off for saying so, she’d find it pretentious, but she really was a pioneer, both as a woman writing at The New Yorker and as a truly innovative artist, someone who helped change and shape non-fiction writing in English,” Remnick wrote.

“It’s sort of like having sex,” she once wrote.

Ross’ approach, later made famous by the “New Journalists” of the 1960s, used dialogue, scene structure and other techniques associated with fiction writers. She regarded herself as a short story writer who worked with facts, or even as a director, trying to “build scenes into little story-films.” In 1999, her 1964 collection of articles, “Reporting,” was selected by a panel of experts as one of the 100 best examples of American journalism in the 20th century. The group, assembled by New York University, ranked it No. 66.

“She is the mistress of selective listening and viewing, of capturing the one moment that entirely illumines the scene, of fastening on the one quote that Tells All,” novelist Irving Wallace wrote in a 1966 New York Times review of her work.

Short and curly-haired, unimposing and patient, Ross tried her best to let the stories speak for themselves, but at times the writer interrupted.

In the late 1940s, Hemingway came to New York for shopping and socializing and Ross joined him as he drank champagne with Marlene Dietrich, bought a winter coat and visited the Metropolitan Museum of Art, flask in hand. She presented the author as a volatile bulk of bluster and insecurity, speaking in telegraphic shorthand (“You want to go with me to buy coat?”) and even punching himself in the stomach to prove his muscle.

Ross was friendly with Hemingway — she liked most of her subjects but her article was criticized, and welcomed, as humanizing a legend. “Lillian Ross wrote a profile of me which I read, in proof, with some horror,” Hemingway later recalled. “But since she was a friend of mine and I knew that she was not writing in malice she had a right to make me seem that way if she wished.”

Not long after, Ross went to Hollywood to report on director John Huston as he worked on an adaptation of Stephen Crane’s Civil War novel “The Red Badge of Courage.” She soon realized that the movie was more interesting than any one person — she was witness to a disaster. Ross’ reports in The New Yorker, released in 1952 as the book “Picture,” were an unprecedented chronicle of studio meddling as MGM took control of the film and hacked it to 70 minutes.

Praised by Hemingway among others, “Picture” was a direct influence on such future Hollywood authors as John Gregory Dunne (“Studio”) and anticipated the nonfiction novel that Truman Capote perfected a decade later with “In Cold Blood.” Huston’s daughter, actress Anjelica Huston, became a lifelong friend.

“My parents loved and respected her, and trusted her. She was, they would say, different from other reporters,” Huston wrote in the foreword to the book’s 50th anniversary edition.

Deeply private even around her New Yorker colleagues, Ross did step out in 1998 when she published “Here But Not Here,” a surprising and explicit memoir of her long-rumored, 40-year liaison with New Yorker editor William Shawn, a mating of secret souls allegedly consummated in a bedroom once used by Dietrich as a clothes closet.

“We were drawn to each other from the first by all the elusive forces that people have been trying to pin down from the beginning of time,” Ross wrote.

William Shawn had died six years earlier, but his widow was still alive when the book was published, leading New York Times writer (and former New Yorker deputy editor) Charles McGrath to call it “a cruel betrayal of the Shawns’ much-valued privacy, a tactless example of the current avidity for tell-all confessions.”

While involved with Shawn, Ross adopted a son, Erik, who in later years would accompany his mother on assignments. Her New Yorker work was compiled in several books, most recently “Reporting Always.”

Born in Syracuse, New York, she was always more comfortable as an observer and played hooky just to hang around professional newspaper offices. She graduated from Hunter College, worked at the liberal New York City daily PM, then was hired by The New Yorker in the mid-1940s, when the magazine was looking for women writers because so many men were serving in World War II.

“We have sent her on stories ranging from in subject matter from politics to uplift brassieres, and she’s done splendidly by both,” PM editor Peggy Wright Weidman wrote to Shawn. “Another baffler is that she likes to work and does so, at any hour of the day, night, or weekend, with concentration and no nonsense.”