Diana C.C. Zeydel is global chair of the Private Wealth Services Practice and focuses her practice on estate and tax planning for high-net-worth individuals and families, including intra-generational wealth transfer strategies and business succession planning. Her practice includes planning for United States and non-United States citizens and residents. Diana also assists clients with litigated probate, trust, and guardianship matters, and represents clients before the Internal Revenue Service in matters involving fiduciary income tax and estate, gift, and generation-skipping transfer tax controversies. She represents corporate and individual fiduciaries in connection with the administration of estates and personal and charitable trusts. Diana also assists clients in preparing prenuptial and postnuptial agreements. She has participated in numerous projects involving governmental submissions in the estate, gift, and GST tax areas and serves as an expert witness in cases involving her practice areas.

Diana is a frequent lecturer and author and has spoken on a variety of topics before the American College of Trust and Estate Counsel, the Real Property, Trust and Estate Section of the American Bar Association, the Real Property, Probate and Trust Law Section of the Florida Bar, as well as various other professional organizations. She received the "Best in Wealth Management" Americas Women in Business Law Award given by IFLR/Euromoney in 2014 and 2019. She has been recognized by her peers as "a key figure in shaping the whole wealth management legal profession" and "an incredibly intelligent and creative practitioner, particularly on the tax and business restructuring side." Chambers USA Guide.

Prior to attending college and law school, Diana was a professional ballet dancer. She received her training on a full scholarship at the Joffrey Ballet School in New York, and was awarded an apprenticeship with the Company. She instead accepted an offer to join the Chicago Ballet, where she was quickly given the opportunity to perform soloist and principal roles.