PHOTOGRAPH COURTESY EVERETT COLLECTION

A new biography of the late, brilliant comedian Phil Hartman, “You Might Remember Me: The Life and Times of Phil Hartman,” by Mike Thomas, came out last week. It’s a good title, evoking Hartman’s “Simpsons” character Troy McClure (as in “You may remember me from such spinoffs as ‘Son of Sanford and Son’ and ‘After Mannix’ ”) and inspiring our wistfulness. Hartman died in 1998, long enough ago that a biography seems motivated by good will rather than some other impulse. Picking up the book, whose cover features two of him—the smiling performer and the content, assured man—makes you feel like he’s back. Hello, Phil.

Hartman’s death, all these years later, still feels shocking. He was shot to death, in bed, by his wife, Brynn Hartman, who was intoxicated and upset, and who a few hours later shot and killed herself, while their son and daughter were asleep in the house. Friends and relatives knew of the couple’s difficulties—Phil could be remote, and Brynn, who struggled with addiction, could be volatile—but the rest of the world did not. To fans, Hartman had seemed happy, healthy, and fine. Onscreen, he tended to play authority figures who, whatever their flaws, were in control. Their authority was part of the joke: in his roles on “Saturday Night Live,” “The Simpsons,” “NewsRadio,” and elsewhere, pompous blowhards were his specialty. He also excelled at charming flimflam men, smooth-talking sleazebags, self-important airheads, didactic sellouts, old-time movie heroes, and cigar-chomping jerks. Then there was his gentle side, also authoritative: the buttery voice-over introductions to “Deep Thoughts,” “Wayne’s World,” and “Daily Affirmations with Stuart Smalley,” and his very tidy character the Anal Retentive Chef, who made it seem sweetly reasonable to dispose of bell-pepper scraps—those “little nasties”—inside paper towelling, aluminum foil (“This way it won’t leak onto other garbage”), and a paper bag, folded over and taped shut. “All ready for the trash,” he says.

Part of the pleasure of watching Hartman perform was the feeling of being in the hands of a competent professional, a true adult, even if that adult was ridiculous. It seemed impossible that the man behind those characters would be in a domestic situation that would end in his murder. Some entertainers lead lives that seem dangerous; Hartman wasn’t one of them.

“You Might Remember Me” helps to explain what happened. Thomas, a writer for the Chicago Sun-Times and the author of the book “The Second City Unscripted,” from 2009, tells Hartman’s story from the beginning. He was born in 1948, in Brantford, Ontario, and was one of eight children. The family moved around and ended up in suburban Los Angeles, and in his teen years there Hartman surfed, drew, smoked pot, acted in theatre productions, dated girls, and did impressions to entertain his friends. As a young adult, he kept surfing and smoking pot, and he also consulted the I Ching and numerology, had love affairs, and roadied for a band. He married in his early twenties, in 1970, and divorced in 1972. In 1973, he played Harold Hill in a production of “The Music Man,” which would come in handy later in his career, and began working, designing album covers for his brother’s music business. In 1975, he joined the Groundlings, the L.A. improv company.

As Thomas tells it, Hartman was instantly good, a performer whose “utter commitment begat brilliance,” an indispensable “utility player” who could be “counted on in all scenarios.” Jon Lovitz, a Groundling then, too, considered Hartman a “big star,” someone who could be told to play a shoe salesman and deliver something jaw-dropping: “Whatever he was going to imagine or say was nothing you could imagine or think of. … He could do any voice, play any character, make his face look different without makeup. He was king of the Groundlings.” He began to get voice work and small film roles. Meanwhile, he kept his day job. He helped Paul Reubens, another Groundling, develop his Pee-wee Herman character, as well as his successful stage show. In 1982, Hartman married his second wife; they divorced in 1985.

He met Brynn Omdahl at a party in 1985. Sober then, Omdahl had had trouble with cocaine and alcohol in the past. Thomas writes, “When Phil met Brynn, he may well have been at his most vulnerable state in years”—his second marriage’s ending had shaken him, and his performing career wasn’t taking off. Omdahl was strikingly beautiful, Thomas writes, and the “affections of a statuesque blonde” may have bolstered Hartman’s “deflated self-image.” But their relationship, he says, was “bumpy from the get-go.” Ed Begley, Jr., among others, told Thomas about the couple’s dramatic arguments and reconciliations.

That summer, “Pee-wee’s Big Adventure,” which Hartman helped to write, came out, and was a success. In the fall, Reubens, as Pee-wee, hosted “Saturday Night Live,” and Hartman and John Paragon were hired to help write material for the episode. Lorne Michaels was impressed by Hartman, and he said so to Reubens’s manager, who, Thomas writes, “told him, in effect, ‘You ain’t seen nothin’ yet.’ ”

In 1986, after eleven years in the Groundlings, Hartman was hired by “Saturday Night Live,” as both a performer and writer. Michaels added Hartman, Jan Hooks, Dana Carvey, Victoria Jackson, and Kevin Nealon to a cast that included Dennis Miller, Nora Dunn, and Lovitz. The writers, Al Franken, Jack Handey, and Robert Smigel among them, created some of the smartest, funniest sketches in the show’s history.

Thomas’s book, not surprisingly, really takes off when it gets to the “S.N.L.” years, illustrating how the skills that Hartman had honed in the Groundlings made him a key cast member who made everyone look good and helped to improve the show. Hartman, who was older than many of his peers and professional by habit, excelled at both lead and supporting roles. In his first year, he did some terrific work, including in one of the greatest “S.N.L.” sketches of all time: Smigel’s inspired imagining of Ronald Reagan as the Iran-Contra mastermind, in which Reagan’s affect of gentle naïveté is a cover for his ruthless West Wing scheming. Hartman ratchets between personas thrillingly. When he’s barking out strategies to his staff and an aide announces the arrival of a Girl Scout for a photo op, he says darkly, “This is the part of the job I hate,” then turns into the lovable grandpa we recognize. Then, Girl Scout gone, he claps his hands, yells, “Back to work!,” and resumes ordering his henchmen around.

“Saturday Night Live” showcased the range of Hartman’s talents. He had a gift for finding the soul, or the id, in his characters. His Sinatra was aggressive, abrasive, bigoted, a bit of a thug, and delicious to watch. His Peter Graves was so self-satisfied that he didn’t seem to know or care that he didn’t understand anything he was doing. His Phil Donahue didn’t realize that he’d become absurd. In fake ads, in his Unfrozen Caveman Lawyer sketches, and seemingly everywhere, he played with the salesmanship at the heart of American life, liberating us from its oppressiveness for a while. And his Clinton, when the time came, was definitive: a McDonald’s-loving, shake-slurping mooch whose warmth, desire for McMuffins and McRibs, foreign-policy acumen, and daily jog are all part of one blob of genius and insatiability and ego. In scenes with Hooks, his “work wife,” as Thomas puts it, he did this as part of a couple: Donald and Ivana Trump, Jim and Tammy Faye Bakker, Beauty and the Beast, Bill and Hillary Clinton. Because of his “steadying influence” and “rock-like presence,” and because he helped her to overcome her stage fright, Hooks nicknamed him “the Glue.” Soon, everyone called him that, sometimes chanting it at table reads when he made the writers’ pieces sound good.