Firm Overview

Concentration in Family Law

Example cases

Divorce; Post-decree matters; Custody issues; Paternity cases; Mediation

Main Office

Joliet Office
56 North Chicago Street
Joliet  IL  60432

  • (815) 727-2100
  • (815) 727-2121

Office Information

Office Hours

Monday through Friday, 8:00 a.m. to 4:30 p.m.

Office Manager

Arielle Barbosa

Emergency After Hours


Languages Spoken


Erin Webster O'Brien, P.C., will dedicate focused, personal attention to your case. She is committed to resolving even the most delicate family legal issues. Call 815-727-2100 to set up a consultation today.
Erin Webster O'Brien, P.C., formerly Erin Webster O'Sullivan, P.C., is dedicated to serving clients throughout Will County and Grundy County who are in need of legal assistance in several areas of family law, including: Divorce, Post-Decree Divorce, Child Custody, Child Support, Pre-Nuptial Agreements, and more.

Is your firm willing to help a client with one discrete part of a case, without taking on the whole case?

If a client wants me to file an Appearance on his/her behalf, it will be in relation to the entire case rather than a particular issue.

What are your policies about dividing work within the firm to make the process most cost-effective for the client?

My paralegal does the paperwork and handles day-to-day communication with clients to keep costs down, as she bills at a fraction of the cost that I do.

How frequently does your firm use mediation, arbitration, or collaborative law to resolve cases?

Very often.

Does your firm provide pro bono legal services or otherwise participate in your community?

Not at this time.

What distinguishes your law firm from others?

Customer service and keeping the clients informed are the keys to handling such delicate family law issues.

Is your firm willing to review documents prepared by clients?

Yes, a client can pay a consultation fee and I will review the already-prepared documentation with him/her.

Is your firm willing to coach clients who want to represent themselves?


Erin O'Brien

Ms. O'Brien was licensed as an attorney with the Supreme Court of Illinois in November, 2004 and the United States District Court for the Northern District of Illinois in January, 2005. Since her admittance in 2004, Ms. O'Brien was employed as an associate attorney at Chuck Bretz & Associates, P.C. where she concentrated in family law, but also had litigation experience in criminal defense, personal injury, and administrative hearings. She opened her own law practice in November, 2008 and concentrates in family law.

Ms. O'Brien is active in the following organizations: Will County Bar Association (board member); Will County Women's Bar Association; Illinois State Bar Association; American Association for Justice; American Bar Association; Rotary Club of Joliet; Cambridge Who's Who Registry of Executives, Professionals, and Entrepreneurs; and National Association of Professional Women. She has also served as a coach for the Lewis University Mock Trial Team in 2007.

In March, 2008, Ms. O'Brien earned a Professional Certification in Divorce Mediation Skills Training from the School of Continuing Studies at Northwestern University. Shortly thereafter, she branched out from the typical family law litigation and became a Fellow of the Collaborative Law Institute of Illinois (CLII) and of the International Academy of Collaborative Professionals. More information about collaborative law can be found at

Ms. O'Brien was recently named a 2015 Top 40 Lawyer Under 40 in family law by The American Society of Legal Advocates.
  • Bar Number:
    Illinois , 2004
  • Lewis University
    B.A. , 2000
    Double majoring in Criminal / Social Justice and American Studies (History Department)
  • DePaul University College of Law
    J.D. , 2004

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