Few transitions of power are more fraught with peril than the introduction of a new actor into the lead role of a long-running show, yet the BBC’s reboot of “Doctor Who” ushers in promising new lead Matt Smith (as well as newly promoted showrunner Steven Moffat) with disarming nonchalance. Sharply satirical and playfully dorky without getting bogged down in its own mythology, this iteration should continue to broaden the show’s appeal beyond its twin fanbases of Comic-Con lifers and Anglophiles, though both groups will certainly give their seal of approval.

Rapidly approaching its 40th year, the venerable British staple concerning the extraterrestrial Doctor and his time-traveling police box has undergone this transition before. Nearly a dozen times, in fact, as clever early writers had the foresight to enable the Doctor to regenerate into an entirely new body whenever necessitated by circumstances — or casting. Yet most recent lead David Tennant left deeper fingerprints than most on the role, modernizing the character by leavening his essential zaniness with a certain cosmopolitan charm.

Relative unknown Smith makes for a somewhat more traditional Doctor, perpetually distracted and cheerful, but also exhibits more than a touch of “Monty Python” in his abstemious physical comedy, hopping over fences and spewing mouthfuls of yogurt with a strange amount of dignity. Smith is the youngest actor to limn the role, though he doesn’t necessarily look it; he’s angular and weirdly ageless — at times it seems like an alien’s vision of a good-looking young man. Which is, of course, totally appropriate.

Equally winning is new companion Amy Pond (Karen Gillan), a spunky, gorgeous redhead with a Scottish accent and a job that should appeal to the latent British lecher inside all of us. Introduced as a child earnestly praying to Santa, Amy has a run-in with the Doctor, who crash-lands in her backyard immediately after regenerating into his current form.

Raiding her fridge and promising to return to pick her up in five minutes, the Doctor miscalculates and winds up reappearing 12 years later, to find an adult Amy who has undergone heavy therapy to cure her obsession with him. While it’s unusual to see the Doctor as an object of desire, it’s also a clever touch that should serve the series well as she accompanies him on his adventures — after all, Amy is essentially just a diehard “Doctor Who” fan.

First episode “The Eleventh Hour” boasts a plot that should seem old hat to those diehards (shape-shifting alien tapeworm escapes from prison, makes a threatening prophecy, Doctor has 20 minutes to save the earth, etc., etc.), but veteran series writer Moffat litters it with just enough sly innuendo and sight gags to recall the series’ onetime scripter Douglas Adams. (The crowds of people calmly videotaping the apocalypse on their iPhones registers as particularly clever.)

Visual effects, long the show’s albatross, still do little to disguise the series’ TV-level budget, though the tech crew has gotten far more clever with its limited resources.

Doctor Who

BBC America, Sat., April 17, 9 p.m.

  • Production: A BBC Wales production for BBC One, distributed by BBC Worldwide. Produced by Tracy Simpson; executive producers, Steven Moffat, Piers Wenger, Beth Willis; directors, Adam Smith, Andrew Gunn, Jonny Campbell, Catherine Morshead, Ashley Way, Toby Haynes; writers, Steven Moffat, Mark Gatiss, Toby Whitehouse, Simon Nye, Chris Chibnall, Richard Curtis, Gareth Roberts;
  • Crew: Camera, Owen McPolin; production designer, Edward Thomas; editor, Jamie Pearson; music, Murray Gold; original theme music, Ron Grainer; costume designer, Ray Holman; art director, Stephen Nicholas; vfx editor, Ceres Doyle; supervising sound editor, Paul McFadden; assistant director, John Bennett. Running time: 64 MIN.
  • Cast: The Doctor - Matt Smith Amy Pond - Karen Gillan Rory Williams - Arthur Darvill With: James Corden, Tony Curran, Iain Glenn, Alex Kingston, Helen McCrory, Ian McNiece, Sophie Okonedo, Bill Paterson, Meera Syal, Nina Wadia.
  • Music By: