Noth says the idea of playing Morgan intrigued him.
"He's sort of maligned today," Noth says. "But two times in our history he saved our banking system from falling apart and saved the country from bankruptcy and depression. He was a patriotic man. But he liked to make money, too.
"It was fun to come into this film and remind people whose wallet it was that was building the Titanic," says Noth. "Morgan wanted the ship done right, and he wanted it safe. But the bureaucracy below him equivocated a lot."
Everyone knows the resulting tragedy. But that familiar outcome looms just beyond the final fade-out of "Titanic: Blood and Steel," itself the largely untold story of how the ship came to be.
Also appearing is Derek Jacobi ("The King's Speech, "The Borgias") as Lord William Pirrie, chairman of the Harland and Wolff shipyard in Belfast, Ireland, where the ship was built.
Kevin Zegers ("Gossip Girl") stars as a young scientist who raises questions about the safety of the ship. Neve Campbell ("Party of Five") plays an American journalist reporting on the ship's maiden voyage. And Alessandra Mastronardi ("To Rome with Love") stars as a copyist who, thanks to her skill and perseverance, prospers even in this patriarchal age.
"The film celebrates the complex nature of the project, and all the people who wanted it to happen," Noth says. "This was an industrial age at the advent of new technology. There was a flowering of unions. Meanwhile, there were social issues, including the Catholic-Protestant conflict."
Filming his scenes in summer 2011, Noth sports a bushy, Morganian mustache which, he confides, was artificially applied. "I don't think I have the hormones to grow one like that," he jokes.
But he was denied one makeup touch: the purple, outsized nose that plagued Morgan, caused by a chronic skin disease.
"His nose was a cross between W.C. Fields' and Jimmy Durante's," Noth says, "and I wanted it for the part. But we didn't have time to make it."
Even before J.P. Morgan, Noth has made a TV specialty of important-guy roles that don't necessarily claim lots of screen time.
He was the intermittently seen but somehow ever-present Big on HBO's "Sex and the City" (as well as in two movie versions of the series).
And now he's starting his fourth season as Peter Florrick, a powerful pol (and the philandering husband of series star Julianna Margulies) on "The Good Wife."
As a key but recurring character on that CBS legal drama, Noth says the routine beats his old gig, playing a series lead on "Law & Order" and, later, "Law & Order: Criminal Intent."
"At this point in my life, I like the security of a job," says the 57-year-old actor, "while still having time for my young son and to pursue other creative work."
For instance, he's recently made two indie films — "3, 2, 1 ... Frankie Go Boom" and "Lovelace."
"I just played a cocaine-addicted ex-TV actor in one, and a mafia guy involved in porno in the other," says Noth. He may be best-known as a TV series Bigshot, "but I do a lot of other stuff under the radar."