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Kylee R. Mattoon

Photo of Kylee R. Mattoon
  • Attorney


Clayton, MO




Kylee R. Mattoon is a cum laude graduate of Washington University School of Law. Kylee was a Chief Executive Editor of the Washington University Journal of Law & Policy and participated in the school’s Children’s Rights Clinic, assisting low-income families with adoptions and legal guardianships and representing the best interests of children in child custody and order of protection proceedings. Kylee earned her bachelor’s degree in Human Development & Family Studies from the University of Missouri, graduating summa cum laude. She is a member of the Missouri State Bar, the American Bar Association, and the Bar Association of Metropolitan St. Louis.

Prior to joining Grant, Miller & Smith, Kylee served as a legal intern for the St. Louis City Circuit Attorney’s Office. She was also one of 30 law students nationwide selected for the Equal Justice Works Crime Victims Justice Corps, interning with Legal Aid of Western Missouri in their Human Trafficking Unit.

Before beginning her legal career, Kylee worked with children and families impacted by family violence.

Areas of Practice

  • Family Law
  • Juvenile Law
  • Criminal Defense

Bar Admissions

  • Missouri


  • Washington University School of Law, St. Louis, Missouri
    • Honors: cum laude
    • Honors: Scholar in Law Award
    • Honors: Dean’s Service Award
    • Honors: Dean's List
    • Honors: Two (2) CALI Excellence for the Future Awards
    • Honors: Public Interest Certificate
  • University of Missouri
    • Honors: summa cum laude
    • Honors: Dean's List
    • Honors: Multicultural Certificate
    • Major: Human Development & Family Studies


  • Kylee R. Mattoon & Henry M. Miller, Third-Party Custody: A Path to Custody and Visitation for Non-Parent Caregivers, 67(2) , St. Louis Bar Journal, 13, 2021


  • Kappa Delta