‘EVERY patient needs a hero,” reads the tagline for “Hawthorne,” TNT’s new drama series.

Or, in this case, a superhero.

“Hawthorne” star Jada Pinkett Smith (Will’s wife) might as well wear a cape, instead of hospital scrubs, since her character, chief nursing officer Christina Hawthorne, does everything but perform open-heart surgery in tonight’s series premiere. Maybe they’re saving that for next week?

For a dramatic series to resonate, its viewers need to become emotionally invested in its characters. But the ensemble cast here is flat and one-dimensional — somewhat surprising, since John Masius (“St. Elsewhere“) is one of the show’s executive producers.

Christina is mentor, teacher, patient advocate and compassionate boss rolled into one dynamo. This is a woman who comes into work on her day off — and, in one corny scene, even promises the hospital custodian (!) she’ll try to get him the more expensive disinfectant after he complains about the cost-cutting cheap stuff. Really.

We learn that Christina, who’s raising a rebellious teenage daughter (Hannah Hodson), is also marking the one-year anniversary of her husband Michael’s cancer death, all while directing her staff and butting heads with both hospital administrators and her malevolent, over-coiffed mother-in-law (Joanna Cassidy), who blames Christina for Michael’s demise.

Before the day is through, Christina has saved a few lives (and staff jobs), tossed off some profanity (can they say “bulls- -t artist” on basic cable?) and taught a few life lessons — all underscored with a droning soundtrack that’s grating in that whiny, “Grey’s Anatomy” sort of way.

I’m not buyin’ it. And neither will you.