Diane S. Diel


​Diane S. Diel practices family law including Collaborative divorce and mediation. She brings practical problem-solving skills to your family matter and seeks creative and respectful solutions. Diane has worked on a local and international level to help build the Collaborative Divorce process, and has long been a leader in the legal and professional community. Diane is a former president of the State Bar of Wisconsin and of the International Academy of Collaborative professionals. She is respected by colleagues and the judiciary and has received numerous honors and recognition in her field, including being featured on The Wisconsin Law Journal's Power List and as the 2025 recipient of IACP’s Heart of Service Award for her work in the Collaborative community.​
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Diane is a frequent author, speaker and trainer on family law and legal ethics topics, and has trained and presented on these topics locally and around the world. Diane served the International Academy of Collaborative Professionals as a member of its Ethics and Standards Rewrite Task Force and is a member of its Ethics and Standards committee. Diane has served several terms as a member of the Ethics Committee of the State Bar of Wisconsin and as a member of the Access to Justice Commission, a commission created by the Supreme Court of Wisconsin to develop access to the civil justice system for unrepresented low-income Wisconsin Residents.

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    (414) 224-5355

Professional Activities

  • Member, Association of Women Lawyers – President (1984-1985); Executive Committee (1985); Steering Committee (1980-1985).
  • Member, State Bar of Wisconsin Committee on Professional Ethics (1984-1990, and 2014-2020), International Academy of Collaborative Professionals, Co-Chair, Ethics Task Force and Member, Ethics and Standards Committee (2014-2017).
  • Chair, Lawyer Referral Committee, Milwaukee County Bar Association (1985-1989).
  • Secretary and Governor, State Bar of Wisconsin (1988-1992) and Governor, State Bar of Wisconsin (2000-2004 and 2009-2010).
  • Chairman and Director, Midwest Regional Women’s Bar Conference (October, 1996).
  • Chairman, Southeastern Wisconsin Chapter; Collaborative Family Law Council (2000).
  • Past Chair, Collaborative Family Law Council of Wisconsin, 2002.
  • Co-Chair, Training Committee, Collaborative Family Law Council of Wisconsin, (2003-2006).
  • Treasurer; Association of Women Lawyers Foundation, (2006- present).​
  • Board Member, International Academy of Collaborative Professionals (2007-2013)
  • Past President, State Bar of Wisconsin, effective (2008 – 2009) (Served 3 year term as President-Elect, President and immediate Past President beginning July 1, 2007)
  • President, International Academy of Collaborative Professionals (11/1/10 – 10/31/2011)
  • Chair, International Academy of Collaborative Professionals Ethics and Standards Committee, 2017-2018.
  • Member, Access to Justice Commission, (2017-present).

Community Involvement

  • President, Port of Milwaukee Harbor Commission effective June, 2026 and Commissioner, Port of Milwaukee Harbor Commission (2014-present)
  • Former Member, Professional Dimensions (professional women’s organization); Board of Directors and Community Involvement Director.
  • Former Member, Meta House (an organization helping women with alcohol and drug abuse problems); Board of Directors, including term as President of the Board.
  • Former Member, Greater Milwaukee YWCA Board of Directors.
  • Village of Hales Corners, member of the Police & Fire Commission, with three terms as President of the Commission. (1998-2005).