For a lawyer, what's in a name?

The answer: Practically everything.

Consider that every Am Law 200 firm is named after lawyers. No Exelons or Altrias here—just lawyers' last names strung together.

Within a firm, a lawyer's brand is his or her individual name. There is no product. You are the product.

Which is why—while every professional woman considers the career ramifications of changing her name after marriage—it's a particular dilemma for lawyers. Especially if you've been practicing law for 17 years, painstakingly building a reputation as a first-chair litigator and bar leader. And especially if your new husband's last name—Nyong'o—isn't the easiest to pronounce.

But when Heather Tewksbury married Dr. Omondi Nyong'o in December before 150 family members and friends (including his cousin, the Academy Award-winning actress Lupita Nyong'o, plus 30 of his relatives from Kenya), the 43-year-old Wilmer Cutler Pickering Hale and Dorr antitrust partner was adamant: She would change her last name to Nyong'o.

So how hard is it to say? Honestly, not that difficult, although Jimmy Kimmel once did a segment of news anchors butchering Lupita Nyong'o's name. (For the record, here's Lupita saying it.)

“A lot of people might take the easy route and be known personally as 'Heather Nyong'o' and professionally as 'Heather Tewksbury,' but to me, that felt almost duplicitous,” Nyong'o said.

Her identify as a lawyer is so intrinsically tied to her identity as person that separating the two seemed wrong. “So much of who I am…is this career I'm in,” she said.

Nyong'o joined Wilmer from the Justice Department's antitrust division in 2014. At the firm, she's represented clients including Chesapeake Energy in a bid-rigging and price-fixing suit, and former Thornburg Mortgage executives in securing dismissal of charges by the U.S. Securities and Exchange Commission.

As a high-powered litigator, Nyong'o has learned to trust her instincts when making decisions.

In late October, she led Wilmer's trial team in winning acquittal for former Citigroup foreign exchange trader Rohan Ramchandani, who faced a sentence of up to 10 years in prison had he been convicted on criminal antitrust charges of price-fixing in the FX market.

The jury in the Southern District of New York rejected charges that Ramchandani and two other British traders used an online chatroom to rig the $5.1 trillion-a-day currency market. Ramchandani's employer, Citigroup, previously pleaded guilty to violating Section 1 of the Sherman Act paid $2.3 billion in fines.

During trial, Nyong'o recalled that lawyers representing a co-defendant urged her not to call a particular fact witness, insisting it was too risky.

She was torn. The witness would provide emotional testimony, and her gut told her this was something the jurors needed to hear.

She followed her gut. “The entire jury was in tears by the end,” Nyong'o recalled. And afterwards, her co-counsel from White & Case told her it was the best examination of a witness he'd seen in 30 years of practice.

That confidence to trust her instincts—something Nyong'o said she's had to work to develop—also played into her decision to change her name.

“I've definitely had people say 'Why would you do that? You're crazy,'” she said. “But the only reason not to do it would have been fear, like maybe I'd lose business.”

Another factor: Tewksbury is the name of her ex-husband. But Nyong'o said that even if she had kept her maiden name (Steiner) all along, “I think I still would have done this.”

She has yet to appear in court as “Heather Nyong'o” and doesn't know if people will do a double-take when they see she's a green-eyed blonde. (Nor for that matter will people necessarily think it's a Kenyan name—some suppose it's Japanese or Eastern European.)

But she's already encountered colleagues flummoxed by the pronunciation. Last week, Nyong'o spoke on a panel at the American Bar Association's spring antitrust meeting, and was introduced as “Heather Tewksbury.” When she interjected to note her new name, she said the moderator responded, “I didn't even want to try to pronounce it.”

No matter. “I'm so proud of this name,” she said. “People [will] get over it.”

When she married Omondi —an ophthalmologist in Palo Alto, California, who was born in Michigan, raised in Kenya (where his family is politically prominent), and educated in the United States—she said it was almost like a naming ceremony.

Now, the Wilmer partner is fully embracing her new identity. “In this profession, your name is everything,” she said. “This is who I am.”