Mayer Brown Appoints Former A&O Shearman Regional Leader As New Japan Head
Mayer Brown has hired senior Japanese lawyer Masahisa Ikeda to serve as managing partner of its Tokyo office—a move that underscores the firm’s ongoing reset in Asia and renewed investment in Japan.
Ikeda is the former head of A&O in Japan and previously served as co-Asia head at legacy Shearman & Sterling. He left A&O Shearman in the third quarter of 2025.
A Japanese national and the first to become a partner at legacy Shearman & Sterling in 2002, Ikeda has a broad practice spanning capital markets, cross-border mergers and acquisitions, asset management and disputes. He has represented Japanese issuers and underwriters in global offerings and advised corporations on antitrust, anti-corruption and corporate governance matters.
At Mayer Brown, Ikeda succeeds Rupert Burrows, who completed two four-year terms as Tokyo managing partner.
Firm leaders said Ikeda’s hire strengthens its Tokyo-based U.S. law capability, particularly for Japanese multinationals pursuing outbound transactions, investigations and compliance work.
Mayer Brown chair Jon Van Gorp described the appointment as a milestone in the firm’s Asia-Pacific growth strategy, emphasizing a deliberate shift toward targeted lateral hiring to build capabilities aligned with strategic priorities.
“This investment in Tokyo reflects the same intentional, strategic approach to lateral hiring that has defined Mayer Brown's growth trajectory,” Van Gorp said. “In 2025, we became very deliberate about expanding the firm through lateral hiring, empowering leaders of our groups to find laterals that could be immediately helpful in achieving strategic goals—not being opportunistic, but strategic and tactical.
“That philosophy is now extending to Japan in a meaningful way. Our entire partnership understands and supports this orientation towards strategic growth through lateral hiring,” he added.
“The Tokyo expansion demonstrates that we don't see a way to success if we're not always in the market to hire lateral partners. That is fundamental.”
Ikeda’s arrival follows the firm’s energy and projects hires in Tokyo and Singapore just last week, signaling a broader rebuild of Mayer Brown’s Asia platform. The firm added four partners across the two offices—three from Milbank and one from the London boutique Trinity—in what it described as a cornerstone investment to scale its energy and infrastructure finance capability.
In Tokyo, the firm added Milbank project finance partner Andrew Pendleton and counsel Justen Fleming, both of whom spent more than a decade at the firm.
Mayer Brown’s latest Japan hires reshape its Tokyo office, which now has seven partners, four who focus on project finance, primarily in the energy sector.
The expansion marks a renewed push in Asia after Mayer Brown’s 2024 split from its longtime Hong Kong partner Johnson Stokes & Master, which resulted in the firm exiting mainland China and sharply reducing its Hong Kong bench. The separation led to the closure of its Beijing, Shanghai and Vietnam offices and left the firm with fewer than a dozen partners in Hong Kong. Additional departures in Singapore and Hong Kong over the past year further thinned its regional ranks.
“Mayer Brown’s global platform, along with its long-standing commitment to and reputation among Japan’s leading businesses and law firms, makes it the ideal platform for me,” Ikeda said. “The combination creates immediate and compelling synergies, enabling seamless, top-tier U.S. law support for Japanese clients wherever they do business globally. It also allows me to resume decades-long partnerships with leading Japanese law firms and their most important clients.”
Reprinted with permission from the February 19th edition of American Lawyer © 2026 ALM Properties, Inc. All rights reserved. Further duplication without permission is prohibited.
