John T. Berteau is of counsel to the law firm of Williams Parker Harrison Dietz & Getzen, a law firm that has served the Sarasota, Florida, area for more than 90 years. Mr. Berteau focused his practice in the areas of wills, trusts, estate planning and administration. He received his undergraduate and law degrees from Duke University.

Mr. Berteau has served on committees of the American Bar Association and the Florida Bar Association involving estate planning and taxation. He has been a fellow of the American College of Trust and Estate Counsel since 1994.

Mr. Berteau has served on the boards of many charitable organizations. He has served as chairman of the Sarasota Memorial Healthcare Foundation; chairman of Southwest Florida Hospice Foundation; chairman of the Friends of Selby Library; and as vice-chairman of Siesta Key Utilities Authority. He has also served as a director and legal counsel to the Sarasota Chamber of Commerce. He is a past Commodore of the Field Club; past president of Sarasota Girl's Inc. Foundation; and past president of Sarasota Bay Rotary Club. He is a Paul Harris Fellow and has also served several terms as Senior Warden (chief layman) of St. Boniface Episcopal Church.

Mr. Berteau has been included in The Best Lawyers in America 2007–2019, has been named by Florida Super Lawyers magazine as one of the top attorneys in Florida, and has been listed in Florida Trend Magazine's Legal Elite.