At the height of his career, in the late 1960s and early 1970s, film director Mike Nichols was widely regarded as something akin to the nation’s satirist in chief — our principal wit, wag, and wiseacre. He was known first as one half, with Elaine May, of the improvisatory tag team Nichols and May, then as the urbane stage director of such plays as Barefoot in the Park, and, finally, as the sophisticated director of darkly humorous films such as his debut, Who’s Afraid of Virginia Woolf? (1966), and The Graduate (1967). These films were snapshots of the spiritual decline and sexual confusion of the era — Kodachromes of emasculated husbands, unfulfilled wives, and wayward collegians.

Fifty years ago, Nichols, who died in 2014 at the age of 83, directed his greatest and darkest film, Carnal Knowledge (1971). From virtually the first frame, the director’s mixture of mordant social observation and sleek cinematic style are in evidence: In the winding, unbroken opening shot, a student named Susan (a regal Candice Bergen) walks out from the dark into the warm, honeyed light of a college mixer. She catches the attention of two students, Jonathan (Jack Nicholson) and Sandy (Art Garfunkel), the latter of whom warily approaches her but, lacking the nerve to speak, trudges back to his roommate.

The dialogue, by the great cartoonist and playwright Jules Feiffer, is as sharp and spiky as any heard in an American movie — “You struck out,” Jonathan tells Sandy, who replies, “Two more times at bat” — but it’s Nichols’s film grammar that intoxicates: His camera stalks his characters as they move through the mixer, which, in his vision, is closer to a cauldron of romantic discord than a fun social gathering. Nichols’s dreamy, gliding style tempers the unvarnished anger of Feiffer’s screenplay. Yes, Jonathan and Sandy are saying nasty, often unbelievably cruel things, but when Nichols’s camera lingers on Jonathan after he has attempted to betray Sandy, or subtly moves in for a close-up of Jonathan’s sad-sack live-in girlfriend, Bobbie (Ann-Margret), we feel pity for them. They are not mere vessels for social commentary but human beings.

Nichols’s directorial gifts invariably added complexity to what could be rather tediously cynical material — and hinted that he didn’t fully share in that cynicism — but it was only after a professional crisis that his films began to show another side of his nature. In 1975, on the heels of a pair of films admired by neither critics nor audiences, Nichols called off a Neil Simon–scripted comedy early into shooting. Upon his return to the director’s chair, with Silkwood in 1983, he began to use his signature style — smooth, crystalline — to tell stories that emphasized the decency of people rather than their duplicity, that were alert to their potential for transformation instead of dwelling on their inability to transcend their lot in life. In Working Girl (1988), the gutsy heroine Tess McGill (Melanie Griffith) is introduced as a lowly, Staten Island Ferry–riding worker bee, but by the time of the film’s triumphant concluding shot, she is firmly ensconced in one of Manhattan’s glistening towers — in an office with a window, no less.

Those who celebrated Nichols for his more acidic early films never quite forgave what they perceived as a softening in his work. “He knows I don’t like a lot of the stuff he does,” Buck Henry, the screenwriter of The Graduate, told The New Yorker in 2000. “I think it’s beneath him.” The director’s evolution from café-society cynic to openhearted sentimentalist is one of the major themes of Mark Harris’s engaging, exceptionally well-researched new biography, Mike Nichols: A Life.

“There was a Nichols they liked and a Nichols they hated,” Harris writes, referring to how the cognoscenti perceived Nichols’s work. “The Nichols they liked was the acid anatomist of human behavior whose movies were extensions of his barbed, unsparing routines with Elaine May in which vanities and pretensions were laid bare almost prosecutorially. The Nichols they hated was a valorizer of the celebrated and well-to-do.” More than most accounts of the filmmaker, Harris’s biography regards Nichols-the-anatomist and Nichols-the-valorizer as two sides of the same coin.

The elder of two sons born to a Jewish physician and his wife in Germany in 1931, Nichols had a challenging childhood: At the age of four, an allergic reaction to a whooping-cough vaccine rendered him permanently bald. (He began to wear a wig as an adolescent.) Then, in flight from the Nazis, Nichols’s family emigrated to the United States in 1939. Nichols seems to have had from an early age a sense of gratitude for having landed in what became his adopted country. “The first thing I saw getting off the boat was a kosher deli, and in the neon sign were Hebrew letters,” Nichols said in an interview. “I said to my dad, ‘Is that allowed?’ And he said, ‘Here, it is.’ And from then on it was fun stuff. We’d never had food that made noise like Rice Krispies. Or drinks that were alive like Coke.”

Nichols was surely an outsider, but instead of bitterly embracing that role, he worked, by luck and pluck, to transcend it. Harris persuasively argues that the lordly, disdainful tone Nichols adopted in his routines with May was a kind of social coping mechanism he developed upon entering the University of Chicago in 1949. “Nichols’s hauteur — for the first time since immigrating, he decided to seem more European — was an anxious reaction to a kind of environment he had never before experienced,” Harris writes. He adds that Nichols’s “dry detachment” was “the only acceptable mode of self-presentation for a young man who wanted a great deal” but took “great care never to look or sound too excited about anything.”

And Nichols wanted a great, great deal: Harris describes him falling into the circle of photographer Richard Avedon, who, like a real-life Henry Higgins, counseled his protégé on “who should decorate his apartment” and “where to buy the best caviar.” Harris recounts the financial success that accompanied Nichols’s career milestones: Nichols and May walked away with a small fortune from their various engagements, and when Nichols was signed to direct Who’s Afraid of Virginia Woolf?, he commanded a salary of $250,000, “a news-making sum for a first-time director.”

All of this money bought Nichols a life of material comfort that must have once seemed remote. This is the rare biography of a filmmaker that does not take as a given its subject’s wealth and influence but actually explains what he did with them: In the mid ’60s, newly divorced from the first of four wives, Nichols purchased an apartment in the famous Beresford building on Central Park West and, with the acquisition of a single colt, began breeding Arabian horses, an activity to which he brought a showman’s brio. Decades later, Nichols invited some of his closest pals, among them Jacqueline Onassis and Warren Beatty, to a horse auction. “They were promised a spectacle, and they got one,” Harris writes. “Nichols hired Broadway designers to light the track on which his horses would be brought out in a carefully sequenced procession. He engaged a quartet of musicians to play as each horse appeared.”

Given a fresh lease on life thanks to his final marriage, to broadcaster Diane Sawyer, Nichols, by the late 1990s, was enjoying the life of Riley: “There were new restaurants to try, new plays to drag Sawyer to, new people to have dinner with afterward, whether from her world or his.” Harris sometimes falters in his assessment of the films produced by the fulfilled, satiated Nichols as compared with the lean, hungry Nichols. He writes appreciatively of Working Girl but gives too much space to critics offended by its purported violation of “the counterculture ethics that they believed Nichols had once represented,” and he has no time for mainstream entertainments such as Re­garding Henry, a 1991 drama starring Harrison Ford as an attorney whose brain injury leads to an improvement in his disposition. Yet the film is as touching as, and no sillier than, a Douglas Sirk melodrama. And Harris is simply wrong that the film, shot by Carnal Knowledge cameraman Giuseppe Rotunno in pleasing long takes that breathe in the opulent environs of rich New Yorkers, “has the flat, bland lighting and framing of a typical early-1990s television drama.”

Harris eases up when Nichols’s choice of material is perceived to be edgier, as with the dark dramas Wit (2001) and Closer (2004), but he writes of the Clinton-inspired Primary Colors (1998) as though it were insufficiently sharp and instantly dated — in fact, it is the rare political drama to emphasize its subjects’ humanity — and makes a big deal out of the fact that anti-American aspects of Charlie Wilson’s War (2007) were, rightly, toned down in the final edit. In the end, Harris errs when he judges certain of Nichols’s confections to be disappointments or betrayals.

More often, Harris properly perceives Nichols’s increasingly life-affirming work to be a reflection of his hard-won joy — a journey, from cynicism to contentment, any of us would be glad to make. “Guess where I am!” says Tess McGill, ascendant, at the close of Working Girl, and Nichols himself reveled in his success. Upon winning a Tony Award for directing a Broadway revival of Death of a Salesman in 2012, Nichols began his acceptance speech this way: “You see before you a happy man.” And so he was — thanks to his homes, his hobbies, his blissful marriage to Sawyer, and, yes, his Arabian horses, too.