The calm, modulated voice on the telephone is instantly familiar.

For a generation of baby boomers whose morning routines in the 1970s and ’80s were accompanied by the preternaturally composed presence of one of their own co-hosting NBC’s iconic “Today” show, Jane Pauley is like family.

So when the 63-year-old broadcasting legend recounts her journey with bipolar disorder, it resonates.

“Part of what makes my story relateable is that it could happen to anyone — and it’s nothing to be ashamed of,” Pauley says.

Her ongoing mission: To de-stigmatize all mental-health diseases, because “they are medical conditions that can be treated and managed.”

Out of the blue

Pauley first revealed her bipolar disorder in the best-selling 2004 memoir “Skywriting: A Life Out of the Blue.”

The condition, which is highly inheritable, though not in any of Pauley’s relatives, had lain dormant for the first 50 years of her life.

“I’d never had a ‘manic’ or ‘depressive’ episode, nor exhibited any symptoms that I could view in retrospect as warning signs,” she says. “In fact, the president of NBC News once said, ‘Jane is the most emotionally stable in the business.’”

Her latent bipolar vulnerability was “triggered” in 2000 by treatments for a completely unrelated medical condition: severe recurrent hives.

“I used to get them periodically in strange places — my feet, my lips, my eyelids,” Pauley recounts. “Not terribly telegenic.”

When they began creating respiratory issues, Pauley’s doctor treated them aggressively: with steroidal injections.

“We didn’t know it at the time, but that’s what triggered the disease,” Pauley says.

Notorious “mood destabilizers,” the powerful steroids at first gave Pauley a palpable physical, mental and emotional boost.

“I was bouncing down the halls and full of energy,” she recalls.

The steroids controlled the hives, so she began gradually cycling off the drugs. However, concurrent to decreasing the steroids, she became uncharacteristically depressed, so she was prescribed a low dosage of an antidepressant.

Ineffective initially, after several gradual increases in the antidepressant dosage, Pauley was feeling “super revved-up again.”

Her husband, famed “Doonesbury” cartoonist Garry Trudeau, was the first to recognize something was significantly amiss.

Voluntary hospitalization

Eventually, Pauley’s extended periods of “hypomania” (“hypo” meaning mild) became apparent to her doctor and psychopharmacologist — “and myself,” she concedes.

Here’s how she explained it in “Skywriting”: “[I had been] prescribed an antidepressant for a common unipolar depression I was evidently suffering from. It had unmasked a never-before-suspected vulnerability to bipolar depression … But in a person with bipolar disease, an antidepressant, without the addition of a mood-stabilizing medication, can be dangerous. It produces a bungee-cord effect.”

Thus, in the spring of 2001, she voluntarily checked into a psychiatric hospital for three weeks.

“I’ll need to medically manage my bipolar disorder for the rest of my life,” she says.

Blessed with what her doctors termed “insight” into her disease, Pauley remains vigilant about not letting external factors send her into a mental-health tailspin.

“For instance, after this interview, I’ll wonder: ‘Was I too glib, smug or full of myself?’” she explains. “But now I have the tools to move on from those negative thoughts.”

Reinvention

Pauley’s spot atop the Mount Rushmore of pioneering newswomen was carved long ago. Having replaced Barbara Walters on “Today” at age 25, and then spending another decade and a half co-hosting “Dateline,” has made her broadcasting royalty.

Arguably, though, her evolution into advocate extraordinaire may prove more influential than anything she ever reported from an NBC News set.

Earlier this year, Pauley released her second best-selling book: “Your Life Calling: Reimagining the Rest of Your Life.”

“Because ‘mid-life’ keeps going and going — far longer than it did for our parents — you may need to reinvent yourself a few times,” explains Pauley.

After all, she certainly has.

Pauley originally moved from morning to primetime because, when the younger Deborah Norville joined “Today” in 1989, “I saw the writing on the wall.”

After leaving “Dateline” and writing “Skywriting,” she spent 2005 hosting her own ill-fated, syndicated daytime talk show.

“Even though the show failed, it was the most rewarding professional year of my life,” she says.

Pauley notes, with a laugh, that demonstrating to her and Garry’s three kids that one of them could fail so miserably at something and not be crushed by it was “good parenting.”

In 2009, Pauley rejoined “Today” part-time in the AARP-sponsored segments that became the impetus for her second book.

“Coming back to high-definition TV at age 59 was a bit intimidating,” she admits.

As the latest chapter of Pauley’s storied career unfolds, what she wants everyone to understand about reinvention is, “You don’t have to get it right the first time.”