During her time as President of the St. Louis Breastfeeding Coalition, Erin L. O'Reilly helped to get a Missouri state breastfeeding law passed, obtain 501(c)(3) status for the coalition, and plan and fund the Breastfeeding Photo Project in 2014; helped write a grant for funding to start the I AM: Breastfeeding support group led by leaders in a Black community in St. Louis, which is still operating; as well as participated in many World Breastfeeding Week events over the years and other community events. She has been a volunteer La Leche League leader since 1999 and has led over 3,000 meetings as a Leader, taken countless phone calls, gone on many home visits to moms needing help with breastfeeding, and trained and certified many new La Leche League Leaders to continue the work of breastfeeding support. Erin taught childbirth and breastfeeding classes and worked in the lactation department of a major hospital in St. Louis for 19 years; she worked in the Nutrition and WIC Department in a neighborhood health care center as a Breastfeeding Coordinator from 2007 to 2020.

Erin’s breastfeeding support experience has encompassed a wide variety of situations, and she has worked with many different women who have many different breastfeeding experiences, barriers, and/or supports. She breastfed her own son as well and experienced personally the barriers to breastfeeding, which inspired her to become a La Leche League Leader and an IBCLC to help others have an easier time on their breastfeeding journeys.