Over the course of a nearly 30-year friendship, Rebecca Eisner and Lydia Kelley have shared plenty of milestones. The pair were law school roommates and graduated together from the University of Michigan Law School in 1989. They’ve celebrated each other’s weddings and the births of four sons between them. And they cheered one another through a string of career advancements, including making partner at their respective Am Law 100 firms.

On July 1, the two will be celebrating again as Eisner formally takes the reins as partner-in-charge of the 327-lawyer Chicago office of Mayer Brown. The move comes just over a year after Kelley assumed leadership of McDermott Will & Emery’s Chicago office, which is right around the corner in the Loop.

“The odds of coming out of a class that didn’t have many women, ending up in Chicago and managing to take a leadership role in each of our respective offices…. it’s almost unfathomable,” says Kelley.

Eisner, who advises clients on complex global technology and business outsourcing transactions, is taking the helm of Mayer Brown’s Chicago’s office after a serving on the firm’s partnership board. She replaces corporate partner Frederick “Fritz” Thomas, who has led the office since 2007.

The transition leaves Eisner and Kelley in charge of two of the windy city’s largest law firm offices—McDermott’s Chicago headcount stands at 258, according to The National Law Journal’s latest NLJ 350 survey. They also stand out as the only women appointed leaders among the city’s 20 largest law offices.

Eisner and Kelley say they’ve grappled with plenty of obstacles in the course of their careers, especially in a field where senior advancement is still largely reserved for men. But they say they’ve advocated for each other, and they haven’t been shy about advocating for themselves.

“Women tend to be afraid to ask for things that they want, and this can lead to being undervalued or undervaluing yourself,” Eisner says. “You always have more power than you think you have. This is really important for female associates.”

Kelley, whose practice is centered on transactional tax advice, echoes that sentiment. “Rebecca and I were not afraid to ask questions,” she says. Kelley became McDermott’s Chicago managing partner in April 2014, succeeding Nancy Gerrie.

Both women say they’re glad they’ve graduated from sharing mac and cheese dinners and cheap beer during their law school days. But they still get together regularly, they say, meeting for a cocktail or a meal or just to catch up.

“The ability to share with, learn from, and lean on each other has never wavered,” Kelley says. “Nor has the frequency of all-out laughter in our conversations.”

Reprinted with permission from the June 29, 2015 edition of The Am Law Daily © 2015 ALM Properties, Inc. All rights reserved. Further duplication without permission is prohibited.