Football players have the Super Bowl. Actors have the Oscars. For rabbis, it’s Rosh Hashana.

The Jewish New Year is a time of reflection and celebration. But for clergy, who preach to pews swelled with once-a-year attendees, it is a high-pressure moment: All eyes are on them to come up with the pitch-perfect sermon that will keep congregants inspired, engaged — and awake.

That is why rabbis from New York, Texas and beyond have been known to place a call for an unlikely source of backup: a former advertising executive from the Bronx.

Call her the Rabbi Whisperer. Over the past eight years, Michele Lowe has emerged as a resource for dozens of rabbis, becoming — to her surprise — something like a college-essay coach for the rabbinate. Via word of mouth, her contact information has been passed shul to shul each year by clergymen and women struggling with fine-tuning a phrase, delivering a punchline or solving a bad case of rabbis’ block.

“I call myself the ‘Jew in the pew,’” Ms. Lowe said in a recent interview during a break between clients. “I come and say, ‘I am here, and what do you want me to be thinking about for the next 12 months?’”

This year is one of her busiest: She is editing 33 sermons intended for Rosh Hashana, which begins Friday at sundown, and Yom Kippur, she said. “My job is to help these rabbis find their voice.”

When Ms. Lowe got a call from Rabbi Mara Nathan at Temple Beth-El in San Antonio, they chatted about how to add contemporary sparkle to sermons that would otherwise touch on ancient themes. The answer they came up with?

Barbie.

“On the High Holidays, suddenly you have 1,000 people listening instead of 150,” said Rabbi Nathan, who plans to blend lessons from the “Barbie” movie with those of Rabbi Hillel, the Babylonian theologian born in 110 B.C.E., into a sermon about embracing imperfection.

A decorated advertising executive, Ms. Lowe, 65, rose to prominence in the 1980s for producing well-known commercials for things like Miracle Whip and cat litter. She left the field to become a playwright, finding unusual early traction when her first play, “The Smell of the Kill,” about a trio of women who want to kill their husbands, was produced on Broadway in 2002.

The daughter of an interior designer and a furniture store owner from Massapequa Park, on Long Island, Ms. Lowe turned her critical eye on rabbinical sermons from an early age, when as a child she endured soporific speeches at her family synagogue. “The president of the temple used to stand up and tell people not to leave during the sermon,” she said. “He would get up and everybody would flock to the doors. It was awful.”

But it was not until 2015, when she watched a young rabbi struggle through a service, nervously flipping her loose hair at Westchester Reform Temple in Scarsdale, N.Y., that she decided to do something about it. She offered the woman tips gleaned from writing ad copy (“it has to be compelling; there has to be some drama in it”), as well as stagecraft (“plant your feet; make eye contact”).

And, she advised, wear a ponytail.

The next year she had three more rabbi clients. This year she is juggling 16. “Never in a million years did I dream I would even do it one more time,” said Ms. Lowe, whose clients nearly all lead Reform congregations. “But it’s really meaningful for me to do this work; rabbis work so hard, and there is so much at stake for them.”

Over the course of the new year, Rosh Hashana, and Yom Kippur, the somber day of atonement that follows over a week later, rabbis often give four sermons or more. Often interweaving contemporary culture, Judaic teachings and calls to action, some speeches can be highly politicized, others studiously neutral. They come as a halftime break in long ceremonies of prayers and scripture and are invariably hotly discussed over holiday meals. Rabbis say they receive criticism or praise for their High Holiday sermons all year long.

The pressure to make an emotional mark from the pulpit is real.

Ms. Lowe is part cheerleader, part writing coach. She instructs her clients, who are mainly women, to write three different introductions for their sermons, in different tones, from which they pick the winner. She spends the months leading up to the holidays in Zoom sessions and on shared Google docs, encouraging her clients to dig deeper for personal meaning, or to give their phrasing some punch — or, in Yiddish, a little zetz.

Her advice does not come cheap. Ms. Lowe charges $400 for each one-hour coaching session. That fee includes her prep work: reading and editing the rabbis’ sermons.

One key to a compelling sermon, Ms. Lowe said, is making it personal; often she has to push rabbis steeped in scripture to open up. “I’ll tell them, you have Torah, you have a call to action, it sounds really great,” she said. “But there’s one thing missing — you’re not in here.”

Sometimes, her help is more pragmatic, like the tip she gave Rabbi David E. Levy, now of Temple Beth-El of City Island in the Bronx, to stop him from futzing with his skullcap, or yarmulke, while he spoke.

“I said, ‘go ask your wife what fashion tape is,’” Ms. Lowe said. (Rabbi Levy confirmed that for a time he taped his yarmulke to his head, but now no longer has to.)

Rabbis have sought outside counsel for their sermons ever since the Torah was written, but it is most typically from other religious scholars, said Rabbi Motti Seligson, a spokesman for Chabad Lubavich, a Hassidic Jewish group. The Talmud, the foundational text of Jewish learning, is full of stories of rabbis putting their heads together to hash out the finer points of Judaic principals.

This new year, 5784 by the Jewish calendar, is no different, Rabbi Seligson said: “Rabbis may talk amongst themselves about OK, it’s 5784, and what is important for our congregation to hear, this year?” he said. “The delivery is obviously important, but what would be more important is: What is that message from the Torah this year?”

For Rabbi Nathan in Texas, that message is intrinsically tied up with politics; Ms. Lowe has helped her hone sermons in past years that put a Jewish lens on reproductive rights, the Black Lives Matter movement and welcoming migrants to her city of San Antonio. “You want people to walk away and be talking about what you said,” Rabbi Nathan said, “even if they disagree with you.”

But at Washington Hebrew Congregation in Washington, D.C., where congressional staffers from both parties pray, Rabbi Eliana Fischel and Ms. Lowe have worked on finding meaningful messages that are straight down the middle. “We try not to get into the weeds of politics — mostly because all of my congregation knows it better than I do,” Rabbi Fischel says.

Some of Ms. Lowe’s clients are confidential, concerned to be seen as needing a crutch. At first, Dara Frimmer, a rabbi at Temple Isaiah on Los Angeles’s Westside, was reluctant to share that she had sought help on a sermon.

“There is a fear that rabbis have to be wholly original and brilliant and poised and always have the right words,” Rabbi Frimmer said. But she came to realize that turning to community in a time of need was a profoundly Jewish ideal. “With great pride I wrote at the bottom: ‘Thank you to Michele Lowe.’”

Audio produced by Tally Abecassis.