There is so much “business” the fourth big comic book movie adaptation of the summer has to take care of that, frankly, it’s astounding that director Joe “Jumanji” Johnston is able to take care of it all, and with style.

“Captain America” has to connect this World War II-era hero to modern times. The movie has to tie into all the other Marvel comic book movies that are part of “The Avengers,” because as the title implies, the good captain is “The First Avenger.” It has to deliver the origin myth — how Captain America was born out of a “super soldier” experiment during WWII. The film has to back-engineer its way into the meeting between the Captain (Chris Evans) and the Avenger leader we know as Nick Fury (Samuel L. Jackson), and give us a credible version of future Iron Man Tony Stark’s inventor dad, Howard Stark.

And it has to be fun.

It is. The fourth comic book movie of the summer is the best comic book movie of the summer. Johnston has delivered a light, clever and deftly balanced adventure picture with real lump-in-the-throat nostalgia, with Nazis — who make the best villains — and with loving references to “Star Wars” and “Raiders of the Lost Ark.”

The movie’s first trick was turning hunky Chris Evans (“Fantastic Four,” “Scott Pilgrim vs. The World”) into what the ads in the back of comic books used to call “a 98-pound weakling.” They digitally “Benjamin Button” the guy into Steve Rogers, scrawny shrimp. But with World War II in full fury, Rogers is determined to serve his country, even if that country’s military rejects him as 4F, unfit physically. He signs up for a special unit to be turned, thanks to a serum by Dr. Erskine (Stanley Tucci, in a kitschy accent), into super soldiers. “Zo, you vant to go overzees and fight ze Nazis?”

Erskine picks Rogers because he keeps on fighting hopeless odds when he knows he’s right, and “He’s not a bully.” Rogers sticks up for the little guy.

America needs super soldiers because those pesky Nazis already have one. Johann Schmidt is played by that villain’s villain, Hugo Weaving (“The Matrix”). Schmidt’s Hydra organization is developing super weapons and other super soldiers. And Schmidt has his hands on Norse god Odin’s legendary source of power.

Rogers is treated with scorn by his commanding officer, played by the commanding (and funny) Tommy Lee Jones. Rogers is sent on publicity tours, given a silly costume and a red, white and blue shield. But a little interference by a British agent (Hayley Atwell), a little gadget-tinkering by Howard — father-of-Tony — Stark (Dominic Cooper) and a USO tour to the front lines means this Captain will soon show his mettle.

Being the hero means the normally jokey Evans isn’t given much funny to say. But he brings a proper earnestness to his role. “There are men laying down their lives. I’ve got no right to do any less than them.”

On the face of it, “Captain America” seems like the corniest, most dated of the Marvel superheroes to try and bring to the big screen. One way to get us past that is to frame the story in the Captain’s re-discovery by a new generation — in the present day. The other is by spending money on good actors. Nobody but Jones could drawl about a soldier who will “personally escort Adolf Hitler to the Gates of Hell.” Tucci is marvelous, and as a balance, Toby Jones is brought in as sidekick scientist to Weaving’s perfectly-pitched Schmidt.

Atwell makes a vivacious love interest, and they even spent the cash to land the voracious Natalie Dormer (Anne Boleyn of TV’s “The Tudors”) for a one-off man-eater scene.

It’s too long and it could do with a few more laughs. Why cast the swaggering Evans as the modest Captain America if you’re not going to let him put his quirky stamp on the character?

But then, like Johnston and the movie around him, Evans has so much business and back story to carry that the real marvel of it all is how much fun it actually is.