Ato Essandoh isn’t Jewish. But these days, he’s learning Hebrew prayers and how to lay tefillin for his new role as cardiothoracic surgeon Isidore Latham, an Orthodox Jew, on the NBC drama “Chicago Med.”

“I would describe him as a brilliant surgeon and also very volatile when he’s under pressure, and also a little standoffish,” Essandoh said. “I think his mind works at a higher frequency than the average person and he sometimes has issues dealing with that.”

His introduction in the Sept. 22 season premiere set up a mentorship storyline with Dr. Connor Rhodes (Colin Donnell) and established the importance of his character’s Jewish faith in his daily life. “His head is never bare. You’ll see him wearing a kippah when he’s not in a surgical hat, and tzitzit. I have a full beard,” Essandoh said.

There are rabbinical texts and the Torah in his office alongside medical books, and he will be seen putting on tefillin. “They’re not going to gloss over the fact that this is what he does every morning before he comes to work. He’s a devoted Orthodox Jew,” Essandoh said. “It’s not just lip service.”

Essandoh offered another example. “We shot a scene where it was the Sabbath and he had to work. He can’t touch any machinery, so he’s in his office, sitting in the dark. And he has to have someone press the elevator button.”

All of this was foreign to Essandoh, even though he grew up with “mostly Jewish” childhood friends in New Rochelle, N.Y., where he “went to a ton of bar and bat mitzvahs” and learned some Hebrew prayers. “But as a stereotypical goy, I have only a passing knowledge of what Judaism is,” Essandoh admitted.

To rectify that and help him prepare, producer-director Michael Waxman put Essandoh in contact with Rabbi Capers Funnye, who leads Beth Shalom B’nai Zaken Ethiopian Hebrew Congregation of Chicago. The rabbi explained the different branches of Judaism, laws, rituals and their meanings in great detail. “The information was overwhelming and swimming around in my head. I felt like I was back in Cornell studying organic chemistry,” Essandoh said. “I’ve gotten a fascinating primer into a lifetime of devotion.”

Although he knew there were Black Jews, Essandoh, whose parents are from Ghana, hadn’t realized there was a Jewish community there until Funnye pointed it out. That made Dr. Latham, who is of African heritage, “even more real for me,” he said.

The rabbi also told him about “the debate side of Judaism, the scholars who pore through the Torah and debate the meaning and texture of each passage. Everything symbolizes something,” Essandoh said. “I found it really fascinating.”

Although he played a doctor once before in the series “Copper,” the experience didn’t translate since the show was set in 1864. So Essandoh has observed in the trauma center at Chicago’s Cook County hospital and has learned to stitch wounds on fake skin. “I think I’m a good actor, but to replicate tens of thousands of man hours in surgery is really hard,” he said.

Essandoh had never acted until his college girlfriend dared him to audition for a student-written play at Cornell. He got the role and was hooked instantly. To his parents’ initial disappointment, he didn’t become a chemical engineer, opting instead to study acting at New York’s Acting Studio. “But they’ve been wonderfully supportive,” he said, especially since he’s found steady employment on TV and in films for 15 years.

Now 44, Essandoh got his first big break playing Natalie Portman’s adopted African brother in “Garden State,” released in 2004. “That’s when it started to really ramp up for me,” he said. His credits include “Hitch,” “Blood Diamond,” “The Good Wife,” “Django Unchained,” “Elementary,” “Blue Bloods” and most recently, “Jason Bourne” and the HBO series “Vinyl.”

He loved playing blues musician Lester Grimes in the 1970s-set series, and being directed by Martin Scorsese. The chance to play guitar in it “was a great accomplishment. I’ll never forget that, ever,” he said.

A big fan of what he considers “quirky and compelling characters” in “gritty TV shows” like “Breaking Bad” and “Preacher,” Essandoh hopes to play that kind of role in the future. But right now, he’s enjoying “Chicago Med” and doesn’t mind flying between his home in Brooklyn, N.Y., and the Windy City.

He also co-hosts a podcast with fellow Ghanaian Kwaku Aning called “Radio Zamunda.” “It’s a reference to the movie ‘Coming to America,’ with Eddie Murphy and Arsenio Hall,” he said. “We talk about art and creativity.”

Essandoh has never married but said he is open to it. Perhaps a nice Jewish girl would fit the bill?

“I’ve never dated a Jewish woman. I don’t know how that happened. Growing up near Scarsdale, I should have had at least one Jewish girlfriend,” he said. “Maybe at some point it’ll happen.”