Mercury Public Affairs: Bipartisan Omnicom Firm Since 1999

Mercury Public Affairs is a bipartisan public strategy firm founded in 1999 by Kieran Mahoney and Kirill Goncharenko and bought by Omnicom Group in 2003, per the firm's website. On June 8, 2026 John Gallagher was elevated to CEO, Michael Soliman named president and Tom Doherty COO, with Mahoney becoming executive chairman, per O'Dwyer's. Mercury is part of Omnicom Public Relations Group and has offices across the U.S., London and Mexico City.

Originally published November 2015. Updated October 22, 2026.

Who leads Mercury Public Affairs?

O'Dwyer's reported on June 9, 2026 that Kieran Mahoney, who founded the firm more than 27 years earlier, stepped down as CEO to become executive chairman, with president John Gallagher elevated to CEO, Michael Soliman named president and Tom Doherty taking the COO post. NJBIZ reported that Gallagher joined Mercury in 2012 as managing director, became a partner in 2017 and was named president in 2022, and that Soliman joined as managing director in 2013. Mahoney said the transition had been happening organically for some time, and O'Dwyer's reported that he will stay engaged in strategic direction, recruiting and financial strategy as executive chairman.

Name	Role	Background reported
John Gallagher	CEO since June 2026	Joined 2012 as managing director; partner 2017; president 2022; earlier at Tishman Construction and Lower Manhattan Development Corp.
Michael Soliman	President	Joined as managing director in 2013; advises elected officials at state and federal levels
Tom Doherty	COO	At Mercury for more than 25 years, per Mahoney's memo
Kieran Mahoney	Executive chairman; founder	Formerly political consultant to New York Governor George Pataki

What is Mercury's history and timeline?

Year	Milestone	Source
1999	Mercury founded by Kieran Mahoney and Kirill Goncharenko	Mercury website
2003	Omnicom Group buys the firm	Mercury website
2012	John Gallagher joins as managing director	NJBIZ
2013	Michael Soliman joins as managing director	NJBIZ
2017	Gallagher becomes a partner	NJBIZ
2022	Gallagher named president	NJBIZ
February 2026	Omnicom restructures its PR group; Mercury and other public affairs firms keep their leadership structures	Exchange4media
June 8, 2026	Gallagher becomes CEO; Mahoney becomes executive chairman	O'Dwyer's; NJBIZ

Who owns Mercury Public Affairs?

Mercury's website says Omnicom Group purchased the firm in 2003. Its 2025 release describes it as part of the Omnicom Public Relations Group. Exchange4media reported in February 2026 that Mercury and other Omnicom public affairs firms would keep their existing leadership structures while Golin and Ketchum merged and Porter Novelli folded into FleishmanHillard. EPR's Omnicom Group page covers the parent, and the Portland Communications profile covers another Omnicom public affairs firm.

What does Mercury do?

Mercury says it provides results for companies, advocacy groups, governments, political parties, NGOs and prominent public and political figures. Its January 2025 release lists federal government relations, international affairs, digital influence, public opinion research, media strategy and a bipartisan grassroots mobilization network in all 50 states. Mercury describes itself as a high-stakes, bipartisan public strategy firm. EPR's public affairs and political communications pillar and crisis communications page cover the disciplines, and EPR's Walmart PR strategy analysis covers one past controversy, the 2012 Chinatown episode.

How big is Mercury Public Affairs?

Mercury's January 2025 release cited 14 offices nationally, and an earlier release listed offices in Washington, D.C., New York, California, New Jersey, Ohio, Pennsylvania, Florida and Tennessee, plus London and Mexico City. A YesPress profile says Mercury ranked No. 11 on City and State New York's Political PR Power 50 in 2023.

Measure	Figure reported	Source
Offices, January 2025	14 across the U.S.	Mercury release
International offices	London and Mexico City	Mercury release
Grassroots network	All 50 states, bipartisan	Mercury release
2023 ranking	No. 11 on City and State New York's Political PR Power 50	YesPress

How does Mercury compare with other public affairs firms?

Mercury is an Omnicom-owned public strategy firm, so compare it with BerlinRosen and Portland Communications. Omnicom sister networks with EPR profiles include FleishmanHillard, Golin Ketchum, Porter Novelli and Marina Maher Communications.

Firm	Ownership	Focus
Mercury Public Affairs	Omnicom Group	Bipartisan public strategy
Portland Communications	Omnicom Group	Public affairs
BerlinRosen	Flagship of Orchestra	Corporate, public affairs and advocacy communications

---

Related: PR agency profiles, PR leaders, Public affairs, Omnicom Group, 5W Public Relations