“Life is like a box of dynamite. You never know when it’s going to explode.” These lines aren’t spoken in Felix Herngren’s “The 100-Year-Old Man Who Climbed Out the Window and Disappeared” (original title “Hundraaringen som klev ut genom fonstret och forsvaan”), but they might well have been: the movie, based on a novel by Jonas Jonasson, is like a European version of “Forrest Gump” crossed with “The Ladykillers.” Droll and whimsical, for the most part it’s good fun, a modern take on the old Ealing template.

The titular geezer—physically reminiscent of Tim Conway’s little old man character from the Carol Burnett show—is Allan Karlsson (Robert Gustafsson), whom we meet as a near-centenarian living alone in a rustic cabin with his cat Molotov, a name that indicates his lifelong interest in explosives. When Molotov is killed by a fox, Karlsson responds by blowing the predator up, and is shipped off to a retirement home. On the very day the staff is preparing his hundredth birthday celebration, Karlsson slips through a window and buys a bus ticket to take him to freedom.

At the station, however, he’s accosted by a biker dude (Simon Seppanen) who demands that he look after an oversized suitcase while he uses the restroom. Allan waltzes off with it, of course, not realizing it contains a stash of drug money. Soon he’s being pursued not only by a long-suffering cop Hinken (Sven Lonn), who’s in the dark about the money but tasked with returning the guy to the home, but by various members of the biker gang whose leader Gaddan (Jens Hulten), stuck at home with an ankle bracelet on his leg, is being pressured by drug kingpin Pim (Alan Ford) to get him his money—or else.

Along the way Allan accumulates a virtual family of eccentric helpers: Julius (Iwar Wiklander), a retiree taken with the thought of getting a portion of the cash; Benny (David Wiberg), an aging student working on perpetual degrees because he can never make up his mind about which field to commit to; and Gunilla (Mia Skaringer), a feisty woman who just happens to be housing a circus elephant at her farm. All will become implicated in the accidental death or injury of nefarious pursuers that Allan unwittingly but blithely causes, but in the end the trouble proves to be worth it.

But that’s only half the story. As the chase proceeds, Allan punctuates it with reminiscences about his past that Herngren presents in period flashback, starting with his childhood fascination with dynamite and progressing through episodes that throw him into history-making contact with some of the twentieth century’s most famous or notorious people. He joins the republican forces in the Spanish Civil War, only to save the life of General Franco. Later he helps Robert Oppenheimer solve the last problem obstructing completion of the Manhattan Project, and gets drunk with Harry Truman. Then it’s off to Moscow to meet with Stalin, though that earns him a stay in the Gulag, where his meeting with Herbert Einstein, Alfred’s idiot brother, leads to a catastrophe that causes the Soviet leader’s death. And finally he becomes a double agent for the CIA and the KGB, accidentally passing the Kremlin a misleading remark by Ronald Reagan that induces Gorbachev to tear down the Berlin Wall.

What gives all the mayhem an amiable feel rather than making your jaw drop is the characterization of Karlsson as a perpetually childlike fellow who doesn’t realize the import of what he’s doing. True, that’s the rationale behind the picture’s queasiest sequence, when a crazy doctor in a mental institution concludes that young Allan is racially and mentally deficient and addresses the problem by sterilizing him. But once the plot moves past that point, one accepts Karlsson as a figure similar to Forrest Gump or Chance the Gardener, stumbling through life without a clue while the people around him read him as something other than he is, and try to use him for their own ends. And so he seems innocuous and likable even when he’s doing the most damage.

Apart from an occasional misstep, Herngren and his cast carry off the balancing act between agreeable farce and ghoulishness with considerable panache, with Gustafsson genially making his way through Allan’s many incarnations and Wiklander in particular adding spice as his more cunning compatriot. The technical crew complements their work with appropriate period detail in the flashbacks, and Matti Bye’s upbeat score adds a carnival-like tone to the proceedings.

As an inducement to American audiences, the distributor has tweaked the soundtrack for the US release, dubbing Allan’s frequent voiceovers into English while keeping the dialogue scenes in their original combination of languages, mostly Swedish but sometimes English and occasionally German, Spanish, French and Russian. Rest assured, however, that the film’s polyglot character (and the resultant need for subtitles on a fairly regular basis) won’t spoil your enjoyment overmuch.