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 270 lawyers across 12 offices.
Business lawyers Thomas Harper Cobbs (pictured) and John E. Bishop form a law partnership, Bishop and Cobbs, in St. Louis on Jan. 1, 1901.
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.
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.
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.
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.
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.
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.
Kansas City office opens upon a merger with a local firm.
Jefferson City, Missouri, office opens.
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.
The firm became an LLP and shortened its name – a sweeping trend in the legal industry – to Armstrong Teasdale.
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.
Las Vegas office opens.
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.
Denver office opens, with the acquisition of a Denver-based firm.
Armstrong Teasdale expands to the East Coast with the opening of its Philadelphia office.
New York office opens.
Office opens in Edwardsville, Illinois.
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..
Wilmington, Delaware, office opens.
The firm establishes a presence in Florida with the addition of 12 lawyers and business professionals in Miami.
Washington, D.C., office opens.
Nearly 50 lawyers and business professionals join Armstrong Teasdale from a boutique litigation firm, establishing an office in Chicago.
