It is among the largest law firms based in the United States and provides services for more than 40 major legal practices.

Areas of law practiced by Haynes Boone include Corporate/Securities, Banking & Finance, Energy, Real Estate, Intellectual Property, Labor & Employment, Employee Benefits and Executive Compensation, Technology, Healthcare, and all aspects of Business Litigation.

The firm began handling initial public offerings (IPOs) in the booming Dallas economy.

To promote the firm and grow business outside of Dallas, Haynes Boone sponsored a series on the local public television station in 1984: “A Walk Through the 20th Century” hosted by Bill Moyers.

Haynes Boone represents many of the largest corporations in the world including Bank of America, Exxon, AT&T and others.

v. Neeley which ultimately persuaded the Texas Supreme Court to strike down the state's school finance system.

In 2023, represented a coalition of news organizations seeking a release of records from the 2022 mass shooting in the City of Uvalde.

Senator, Texas’ 10th District Will O’Neill, Mayor, Newport Beach Jason Villalba, U.S. Representative, Texas’ 114th District David Crump, American legal scholar and writer David Epstein, American Law Professor, University of Richmond School of Law Sarah Saldana, Director of the U.S. Immigration and Customs Enforcement Lynne Liberato, First President of the Houston Bar Association and former head of the State Bar of Texas Lisa Normand, Film Producer Heidi Bundren, Chief Legal Officer, Nashville Predators Richard Haynes received the Justinian Award for Public Service in 1989 in recognition of his ongoing service to the Dallas community.

[6] During the 2020 COVID-19 pandemic, Haynes Boone lawyers and staff raised substantial funds for Feeding America [3], local food banks, and frontline healthcare workers.

Each month, the firm staffs a clinic to provide help to those facing a range of legal issues and other pro bono matters through the Dallas Volunteer Attorney Program (DVAP) [4].

Haynes Boone also participates in and sponsors the Lavender Law Career Fair organized by the National LGBTQ+ Bar Association.