Skip to main content


Not yet reviewed

About me

Mary Aileen O'Callaghan is a partner with Smith O'Callaghan & White. She has more than 30 years of experience in the practice of labor and employment law. Prior to joining the firm, Ms. O'Callaghan was in-house counsel for labor and employment matters with a Global 500 corporation and a partner with a prominent labor and employment law firm in Chicago. Ms. O'Callaghan was inducted as a distinguished Fellow in the College of Labor and Employment Lawyers in 1998, a recognition reserved for the most experienced and prominent labor and employment attorneys in the United States, and was selected as an Illinois Super Lawyer in 2006, 2007, 2008, 2009, 2010 and 2011.


Ms. O'Callaghan was named one of the top 50 women lawyers in Illinois for 2010 by Super Lawyers magazine. In addition, she has been recognized by her peers as a Leading Lawyer in the category of Employment Law: Management. Ms. O'Callaghan holds the AV® Preeminet Peer Review Rating, Martindale-Hubbell's highest rating for ethics and legal ability.


Ms. O'Callaghan counsels employers concerning all aspects of employment law, including the ADA, the FMLA, workplace harassment, reductions-in-force, plant closings, compliance with the Older Workers Benefit Protection Act and the Worker Adjustment Retraining and Notification Act, EEO and diversity training, wage and hour compliance, internal discrimination and harassment investigations, and administrative agency investigations and proceedings. She is one of the country's most experienced practitioners in the area of affirmative action; she has prepared and successfully defended affirmative action plans in the public and private sectors for 30 years. Ms. O'Callaghan also maintains an extensive practice in the traditional labor law area. She has assisted clients in more than 200 NLRB representation elections, achieving a success rate in excess of 98 percent. She works with employers to deal with day-to-day human resources decisions and provides counsel to ensure compliance with all state and federal labor and employment laws.


Photos and videos

1060418 1352912831

Practice areas


  1. Employment: 100%

Attorney endorsements

No endorsements

Endorsements from fellow lawyers are an important consideration for many when selecting the right attorney. Be the first to endorse your colleague!

Are you an attorney? Endorse this lawyer

Contact info

Smith O'Callaghan & White

33 N La Salle Street Suite 3800
Chicago, IL, 60602-2666


ILActive And Authorized To Practice Law197708/10/2016
We have not found any instances of professional misconduct for this lawyer.
Avvo contributions
Legal answers
Award nameGrantorDate granted
Top 50 Women Lawyers in IllinoisSuper Lawyers Magazine2012
Illinois Super LawyerChicago Magazine2012
Illinois Super LawyerChicago Magazine2011
Top 50 Women Lawyers in IllinoisSuper Lawyers Magazine2010
Illinois Super LawyerChicago Magazine2010
Leading LawyerLaw Bulletin Publishing Company2010
Illinois Super LawyerChicago Magazine2009
Illinois Super LawyerChicago Magazine2008
Illinois Super LawyerChicago Magazine2007
Illinois Super LawyerChicago Magazine2006
AV Preeminent 5.0 out of 5 Peer Review RatedMartindale-HubbellN/A
Work experience
TitleCompany nameDuration
PartnerSmith O'Callaghan and White1999 - Present
PartnerBrittan Sledz Morris & Slovak1998 - 1999
Adjunct FacultyUniversity of Wisconsin Management Institute1991 - 1998
Adjunct ProfessorLoyola University Chicago School Of Law1980 - 1983
Associate General CounselCanteen Corporation1977 - 1988
Association namePosition nameDuration
College of Labor and Employment LawyersFellow1998 - Present
American Bar AssociationMember1977 - Present
American Bar Association, Labor and Employment Law Section, Employment Rights and Responsibilities, International Law SubcommitteeMemberN/A
American Bar Association, Labor and Employment Law Section, Equal Employment Opportunity CommitteeMemberN/A
Legal cases
Case nameOutcome
Kohnke v. Delta Air Lines, Inc., 932 F. Supp. 1110 (N.D. Ill.)N/A
Taylor v. Canteen Corp., 789 F. Supp. 279 (C.D. Ill.)N/A
McEwen v. Delta Air Lines, Inc., 919 F.2d 58 (7th Cir.)7th Circuit affirmed summary judgment in favor of employer
See all legal cases 
Publication nameTitleDate
Leading Lawyers MagazineEnjoying a Challenge from Unions to Baseball2012
BNA publicationsEmployment Discrimination Law1987
Loyola University Chicago Law JournalLabor Law-Ominous Implication for Public Sector Collective Bargaining in Illinois1976
School nameMajorDegreeGraduated
Loyola University School of LawLawJD - Juris Doctor1977
Mundelein CollegeN/AOther - Bachelors1967