Firm History

Armstrong Teasdale has a rich history with more than 120 years of experience counseling clients through their most complex legal challenges. Over the past century, the firm has grown tremendously and now boasts more than 600 lawyers and business professionals across 18 offices.

1901

Business lawyers Thomas Harper Cobbs (pictured) and John E. Bishop form a law partnership, Bishop and Cobbs, in St. Louis on Jan. 1, 1901.

1920s-1930s

New partners are added regularly in the early years. In 1927, William Armstrong joins as an associate. He becomes a partner in 1931 and Armstrong is added to the firm name in 1939.

1948

Kenneth Teasdale, a good friend of William Armstrong and well-known St. Louis-based trial lawyer, joins the firm. In 1949 Teasdale is added to the firm name.

1950

William H. Webster joins the firm. After leaving in 1970, he goes on to serve as a judge for the U.S. District Court for the Eastern District of Missouri, the U.S. Court of Appeals for the Eighth Circuit, and is to date the only person to have served as director of both the FBI and the CIA. In 2024, the firm dedicated its Executive Conference Room in St. Louis in his honor.

1964

Kenneth Teasdale’s son, Kenneth S.F. Teasdale, joins the firm after a distinguished career in Washington, D.C. with the U.S. Department of Justice.

1987

Steve Cousins is named the first African-American partner at the firm. In 2018, Steve retired from AT and now serves as president and CEO of affiliate Cousins Allied Strategic Advisors, LLC.

1987-1988

The firm merges with the St. Louis firm Schlafly, Griesedieck, Toft & Virtel, becoming Armstrong, Teasdale, Kramer, Vaughan & Schlafly. The firm grows to 83 lawyers. By end of the following year, we are the third-largest law firm in the St. Louis area based on the number of lawyers.

1989

Kansas City office opens upon a merger with a local firm.

1998

Jefferson City, Missouri, office opens.

1998

The firm’s Professional Advancement of Women program is established; today called the Women’s Inclusion Network. The program is one of the first of its type at a private law firm in the St. Louis region.

2000

The firm became an LLP and shortened its name – a sweeping trend in the legal industry – to Armstrong Teasdale.

2004

The firm establishes the Michael C. Tramble Memorial Scholarship Fund at the University of Missouri School of Law, in memory of a promising young African-American associate at the firm who tragically lost his life.

2005

Las Vegas office opens.

2010

The firm is named to the Am Law 200, a list of the 200 largest law firms in the U.S. as ranked by The American Lawyer.

2014

Denver office opens, with the acquisition of a Denver-based firm.

2018

Armstrong Teasdale expands to the East Coast with the opening of its Philadelphia office.

2019

New York office opens with one of the largest real estate practices focusing on cooperative/condominium law in the city. Since 2019, the office has grown to include prominent lawyers across practice areas.

2020

Offices open in Boston, Salt Lake City (pictured), and Edwardsville, Illinois.

2020

The firm establishes a dedicated Diversity, Equity and Inclusion department as an additional investment based on the long-standing success of the firm’s Inclusion Committee..

2020

Wilmington, Delaware, office opens.

2021

The firm establishes a presence in the U.K. with the addition of over 50 lawyers and business professionals in London.

2022

The firm establishes a presence in Florida with the addition of 12 lawyers and business professionals in Miami.

2022

The firm establishes a presence in the EU with the opening of an office in Dublin, Ireland.

2022

Washington, D.C., office opens.

2023

The firm expands its western U.S. presence with the establishment of an office in Orange County, California.

2023

Nearly 50 lawyers and business professionals join Armstrong Teasdale from a boutique litigation firm, establishing an office in Chicago.

Contact Us
  • Worldwide
  • Boston, MA
  • Chicago, IL
  • Denver, CO
  • Dublin, Ireland
  • Edwardsville, IL
  • Jefferson City, MO
  • Kansas City, MO
  • Las Vegas, NV
  • London, England
  • Miami, FL
  • New York, NY
  • Orange County, CA
  • Philadelphia, PA
  • Princeton, NJ
  • Salt Lake City, UT
  • St. Louis, MO
  • Washington, D.C.
  • Wilmington, DE
Worldwide
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Boston, MA
800 Boylston St.
30th Floor
Boston, MA 02199
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Boston, Massachusetts
Chicago, IL
100 North Riverside Plaza
Suite 1500
Chicago, IL 60606-1520
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Chicago, Illinois
Denver, CO
4643 S. Ulster St.
Suite 800
Denver, CO 80237
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Denver, Colorado
Dublin, Ireland
Fitzwilliam Hall, Fitzwilliam Place
Dublin 2, Ireland
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Edwardsville, IL
115 N. Second St.
Edwardsville, IL 62025
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Edwardsville, Illinois
Jefferson City, MO
101 E. High St.
First Floor
Jefferson City, MO 65101
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Jefferson City, Missouri
Kansas City, MO
2345 Grand Blvd.
Suite 1500
Kansas City, MO 64108
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Kansas City, Missouri
Las Vegas, NV
7160 Rafael Rivera Way
Suite 320
Las Vegas, NV 89113
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Las Vegas, Nevada
London, England
Royal College of Surgeons of England
38-43 Lincoln’s Inn Fields
London, WC2A 3PE
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Miami, FL
355 Alhambra Circle
Suite 1200
Coral Gables, FL 33134
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New York, NY
7 Times Square, 44th Floor
New York, NY 10036
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Orange County, CA
19800 MacArthur Boulevard
Suite 300
Irvine, CA 92612
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Philadelphia, PA
2005 Market Street
29th Floor, One Commerce Square
Philadelphia, PA 19103
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Philadelphia, Pennsylvania
Princeton, NJ
100 Overlook Center
Second Floor
Princeton, NJ 08540
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Princeton, New Jersey
Salt Lake City, UT
222 South Main St.
Suite 1830
Salt Lake City, UT 84101
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Salt Lake City, Utah
St. Louis, MO
7700 Forsyth Blvd.
Suite 1800
St. Louis, MO 63105
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St. Louis, Missouri
Washington, D.C.
1717 Pennsylvania Avenue NW
Suite 400
Washington, DC 20006
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Wilmington, DE
1007 North Market Street
Wilmington, DE 19801
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Wilmington, Delaware