From “City Slickers” to the upcoming “Spider-Man: Far From Home,” it feels like Jake Gyllenhaal has been in our lives as an actor for, well, as long as we can remember. (Do you remember him in “City Slickers?” He played Billy Crystal’s son.)

There’s something about those dreamy, droopy eyelids and that impish grin that have burned themselves into the pop culture firmament, long before the days he was shuffling across the heartland in “Bubble Boy” and even through when he was floating through space, trying to escape a mysterious alien entity in “Life.” There’s also “Prince of Persia: The Sands of Time,” which we’ve all agreed that it's best to try and forget ever happened. But with the 37-year-old actor’s birthday coming up on December 19, we decided to celebrate his greatest achievements as an actor, those performances where he transformed himself -- or our expectations of him -- into something better, bigger or more unexpected than ever before.

"Donnie Darko” (2001)

Richard Kelly’s debut film spawned a cult following and two wildly different versions, but the thing that unified both (and audiences) was Gyllenhaal’s turn in the title role. Lumbering through the film as an ordinary teenager prone to mysterious, psychedelic visions, he proved that his fresh-scrubbed good looks could hide deeper complexities that he’d only begun to explore as an actor.

“Brokeback Mountain” (2005)

Ang Lee’s adaptation of Annie Proulx’s short story of the same name changed a lot in Hollywood about perceptions of gay characters, not to mention their stories. It also demonstrated what gifted actors Gyllenhaal and Heath Ledger were.

As the erstwhile focus of the film, Ledger’s Ennis is consumed by the torment of his feelings and the society that condemns them. And Gyllenhaal provides a wonderful, equally tragic counterpoint as Jack Twist, whose juggling of the life he must pretend to lead, and the one he truly wants, ultimately fuels Ennis’ epiphany about what their love truly meant to him.

"Zodiac" (2007)

When David Fincher asks you to play a role in one of his films, you don’t refuse.

Gyllenhaal's turn as Robert Graysmith in “Zodiac” offered a devastatingly believable portrait of obsession as the cartoonist who becomes consumed by his investigation of the real-life San Francisco serial killer. It’s a movie of deliberate and often understated technique, but Gyllenhaal’s performance mirrors Fincher’s cool precision and its inescapable absorption into a criminal case that remains enigmatic even today.

"Enemy" (2013)

Gyllenhaal worked with director Denis Villenueve twice in the span of little more than a year on the films “Prisoner” and Enemy.” But the latter proved to be the bigger challenge of the two, a psychological thriller about a man who believes that he’s encountered his own doppelganger. He soon becomes consumed by imitating, and integrating, their lives into one another. Mirroring himself in ways almost imperceptible, Gyllenhaal conjures a vivid portrait of two men whose identities converge into one.

"Nightcrawler" (2014)

Dan Gilroy wrote for decades before making his directorial debut with this story of a freelance videographer who ruthlessly facilitates and even stages violent scenarios in order to make his name with local news stations. Gyllenhaal stars and co-produces the film, a revelatory, poisonous portrait of ambition run amuck in a profession disinclined to embrace morality in its pursuit of the best headlines. For my money, Gyllenhaal has never been better -- or more frightening.

"Southpaw" (2015)

Eminem was reportedly once considered for the role Gyllenhaal played in this film, Billy Hope, a boxer working towards redemption after the death of his wife. But in addition to transforming himself physically to play a believable and threatening prize fighter, Gyllenhaal lays himself bare in the scenes where his rage and desperation threaten to ruin not only his financial success, but his relationship with his daughter -- the last vestige of his connection to his late wife.

"Stronger" (2017)

Jeff Bauman, a real-life survivor of the Boston Marathon bombing who lost both his legs, is an all-timer role for the actor. The emotional and physical trauma -- as evidenced through his strained romantic relationship post-accident and his relatable struggle to work through and accept the challenges of his rehab and healing process -- is a tricky AF balance that Gyllenhaal pulls off effortlessly. It is both a simmering, internalized performance punctuated with bursts of pain, laughter and tears. Thanks to David Gordon Green's subtle and inspired "ground-level" approach to the drama, the audience experiences every one of Bauman's set backs and triumphs. It's a game of inches down a very long road to recovery, and Gyllenhaal's performance carries you every step of the way.

"Okja" (2017)

There are moments in Bong Joon-Ho’s environmental fable where Gyllenhaal’s performance as Johnny Wilcox, a quite possibly deranged zoologist and TV personality, seem stripped from another film entirely. But in a story about the manipulation not only of the world’s resources (including animals) for corporate narratives, political goals, and personal gain, his contributions galvanize and amplify the film’s themes and showcase both his remarkable versatility and fearlessness.

Even in a small role, he demonstrates a consummate understanding of the film he’s in, and how best to serve it.