Melissa Costello

Melissa R. Costello

Of Counsel She / Her / Hers

Melissa R. Costello counsels and represents private businesses, public corporations, and nonprofit organizations in a variety of litigation and transactional matters. Her practice emphasizes civil employment matters involving harassment, discrimination, wage-and-hour law, state and federal leave laws, ADA, FMLA, COVID-19 issues, discipline issues, contracts, trade secret protection, restrictive covenants, and employment separation.

Melissa has assisted clients in formulating policies, procedures, handbooks, contracts, and strategies to minimize the risk of litigation. She has represented clients in administrative matters, including before the U.S. Department of Labor, U.S. Equal Employment Opportunity Commission, Arizona Attorney General’s Office Civil Rights Division, and Industrial Commission of Arizona.

Melissa has co-chaired jury and bench trials in state and federal courts.

Professional Highlights

Pro Bono Experience

Melissa is committed to providing pro bono employment law counsel for local and national nonprofit organizations.

Professional Activities

American Bar Association, 2001-Present

Arizona State Bar Association, 2001-Present

Maricopa County Bar Association, 2001-Present

Recognition & Accomplishments

Chambers USA, Labor & Employment (Arizona), 2024

Speaking Engagements

Melissa is a frequent presenter on employment law topics throughout the Arizona business community. Presentations include:

"Proposition 207: The Impacts of Legal Marijuana in the Workforce," Association for Corporate Growth - Arizona Chapter Young Dealmakers Cocktails & Conversations, September 1, 2021

“Mental Health Awareness & Avoiding Discrimination Lawsuits,” Ballard Spahr Webinar in conjunction with Paychex HR, April 28, 2021

“Vaccines in the Workplace: What to Do?” Ballard Spahr Webinar in conjunction with Paychex HR, February 17, 2021

"Wellness in the Workplace: Expanding Your Workplace to Include Mental Health," Cancer Support Community of Arizona, August 21, 2020

Board Memberships & Community Service

Cancer Support Community—Board of Directors, 2012-2018; Leadership Council, 2008-2011

Vice Chair, 2015-2016

Governance Chair, 2014-2015

Scottsdale Leadership, 2004-2006

Board of Directors, Recruitment and Selection Vice Chair, 2005-2006


“Benefit of Counsel: Under Wraps,” Staffing Industry Review, May 17, 2021



The University of Arizona (J.D., cum laude, 2001)

The University of Arizona (B.A. and B.S., cum laude, 1997)


Spanish (conversational)