Atty. Mark A. Irwin

Atty. Mark A. Irwin

Mark A. Irwin is a Family Law Attorney and founding partner of IRWIN & IRWIN, LLP, with offices in Fullerton and Newport Beach, California.

Fullerton Fullerton 16 yrs experience 16 year
Call (657) 551-3391 Book Appointment

Child Custody & More Attorney · Serving Fullerton, CA · 16+ Years Experience

Profile Summary

About Mark A. Irwin at a Glance

Mark A. Irwin is a Managing Partner based in Fullerton, California, practicing at Irwin & Irwin, LLP. They have 16+ years of legal experience, licensed to practice since 2010. Their practice focuses on divorce, child custody, family law, employment, and business. Admitted to practice in California (2010). Educated at Western State University College of Law J.D. (—) and University of Southern California’s Annenberg School for Communication & Journalism (—). Serves clients in Fullerton, CA and the surrounding metropolitan area.

Verified attorney profile · Updated October 2026

About Mark A. Irwin

  • Mark A. Irwin is a Family Law Attorney and founding partner of IRWIN & IRWIN, LLP, with offices in Fullerton and Newport Beach, California
  • He is a graduate of the University of Southern California’s Annenberg School for Communication & Journalism
  • Mr. Irwin earned his Juris Doctor in Law from Western State University College of Law
  • He graduated from law school second in his class after earning three Witkin Awards for academic excellence
  • Mr. Irwin worked as a Family Law Attorney for another prominent firm before starting his own practice in 2011 with his wife, Kelly McGrane-Irwin
  • Mr. Irwin is a member of the California State Bar, and the Orange County Bar Association (OCBA)
  • He is also a member of the Family Law Sections of both the OCBA and the California Lawyers’ Association (CLA)
  • Mr. Irwin served on the Orange County Family Violence Council as a member of their Steering Committee from 2004 to 2009
  • He was instrumental in the development of the Orange County Family Justice Center, a one-stop, multi-agency facility in Orange County which provides services for victims of domestic violence, child abuse, sexual assault, and elder/dependent adult abuse
  • Mr. Irwin has almost thirty years of prior experience in law enforcement
  • His investigative background includes complex criminal and administrative law matters
  • Mr. Irwin served as the Vice-President of the non-profit Orange County Family Justice Center Foundation, Inc., from 2006-2009, and he is currently still a member of the Friends of the Foundation
  • Mr. Irwin has also been involved in his neighborhood youth soccer and Little League baseball organizations in past years
  • Mr. Irwin has served as a Mentor with the USC Annenberg Advantage Alumni-Student Mentoring Program
  • As part of this program he mentored seniors completing their undergraduate degrees at the University of Southern California, and helped prepare them to succeed in the “working world.” Mr. Irwin has served as a guest lecturer on Family Law, and Ethics in Family Law, at Western State University College of Law
  • He has also served as a Moot Court competition judge at WSU law school, and has authored several published articles on family law issues
  • Mr. Irwin limits his practice exclusively to Family Law matters
  • He currently accepts cases in Orange, Riverside, San Bernardino and Los Angeles Counties

Practice Areas Explained

Mark A. Irwin's Areas of Legal Practice

Each practice area below reflects the types of cases Mark A. Irwin handles, with a practical overview of what that area of law involves and how it may apply to your situation in Fullerton.

Divorce in Fullerton

A divorce attorney guides you through property division, spousal support, custody, and the final decree — contested or uncontested.

Mark A. Irwin is one of 50,071 divorce attorneys indexed nationally. Browse divorce attorneys in California →

Child Custody & Visitation in Fullerton

Mark A. Irwin is one of 30,982 child custody attorneys indexed nationally. Browse child custody attorneys in California →

Family Law in Fullerton

Family law attorneys handle divorce, child custody, child support, adoption, prenups, and protective orders. Find verified family lawyers near you.

Mark A. Irwin is one of 185,688 family law attorneys indexed nationally. Browse family law attorneys in California →

Employment Law in Fullerton

Employment lawyers represent workers in wrongful termination, discrimination, harassment, wage & hour disputes, and severance negotiations.

Mark A. Irwin is one of 167,770 employment attorneys indexed nationally. Browse employment attorneys in California →

Business & Corporate Law in Fullerton

Business attorneys advise founders and growing companies on entity formation, contracts, financing, M&A, and dispute resolution.

Mark A. Irwin is one of 497,491 business attorneys indexed nationally. Browse business attorneys in California →

Jurisdictional Context

Why Local Counsel Matters in Fullerton

Practicing law in California. Legal matters in California are governed by state-specific rules of civil and criminal procedure, statutes of limitations, and substantive law. Cases originating in Fullerton are typically filed in the local municipal court or the appropriate California state district court, depending on subject matter and amount in controversy. An attorney licensed in California brings working knowledge of local procedural deadlines, judicial practices in this venue, and the substantive law that applies to cases brought here. Out-of-state attorneys generally cannot represent clients in California courts without local counsel or pro hac vice admission.

Fullerton Courts and Legal Process

Choosing a Fullerton-based attorney means your counsel already knows the local docketing timelines, preferred filing formats, and how individual judges typically rule on procedural motions — details that only come from practicing in this jurisdiction day after day. That local familiarity can translate to better strategy, faster filings, and fewer costly surprises.

Looking for additional California attorneys? Browse all attorneys in Fullerton or all attorneys in California.

Frequently Asked

Common Questions About Mark A. Irwin

Where is Mark A. Irwin's law office located?
Mark A. Irwin's law practice is located in Fullerton, California. The firm is Irwin & Irwin, LLP. You can contact the office directly through this profile page.
What practice areas does Mark A. Irwin handle?
Mark A. Irwin focuses on divorce, child custody, family law, employment, business. Each practice area listed reflects experience handling cases of that type in California.
How long has Mark A. Irwin practiced law?
Mark A. Irwin has 16+ years of legal experience and has been licensed since 2010.
Where did Mark A. Irwin go to law school?
Mark A. Irwin earned their education at (—); (—).
How can I contact Mark A. Irwin for a consultation?
You can contact Mark A. Irwin directly through this profile page. Click "Ask the Attorney" to submit a question, or "Schedule a Consultation" to book a meeting. Most claimed-profile attorneys respond within one business day.

Professional Profile

Why Clients in Fullerton Choose Mark A. Irwin

Selecting an attorney is one of the most consequential decisions you can make when a legal matter arises. Below are the core qualities that distinguish Mark A. Irwin's practice in the field of divorce, child custody, family law, employment, and business.

Decade-Tested Legal Experience

Mark A. Irwin brings 16+ years of hands-on legal practice — enough to have navigated the recurring fact patterns, procedural traps, and negotiation dynamics that shape case outcomes.

Broad Practice Area Coverage

Covering divorce, child custody, and family law, Mark A. Irwin can address the full spectrum of a client's legal needs without requiring referrals to separate specialists for each issue.

Local Presence in Fullerton

A Fullerton-based practice means Mark A. Irwin attends hearings in the same courthouses, knows the local clerks, and understands the unwritten scheduling norms that affect every case filed here.

Case Types

Common Legal Issues Mark A. Irwin Handles in Fullerton

Below is a representative sample of the types of matters Mark A. Irwin has experience with under California law. If your situation involves one of these case categories, this attorney may be well positioned to help you understand your options.

Divorce and property division
Family Law
Child custody and support
Family Law
Spousal support (alimony)
Family Law
Prenuptial agreements
Family Law
Wrongful termination claims
Employment
Workplace discrimination
Employment
Wage and hour disputes
Employment
Non-compete agreement review
Employment
Business formation and structure
Business
Contract drafting and review
Business
Partnership disputes
Business
Merger and acquisition support
Business

This list is illustrative, not exhaustive. Contact Mark A. Irwin directly to discuss the specifics of your situation.

Search Reference

How People Find Mark A. Irwin Online

Prospective clients searching for legal help in Fullerton commonly use a combination of the attorney's name and their specific legal need. The following search terms frequently lead people to this profile and to attorneys like Mark A. Irwin.

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If any of the above matches what you searched for, you've found the right profile. Use the contact options at the top of this page to get in touch with Mark A. Irwin directly.

Education & Law School Background

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Western State University College of Law J.D.
- In Progress
—
University of Southern California’s Annenberg School for Communication & Journalism
- In Progress

Bar Admissions & Licensed Jurisdictions

California
Admitted: 2010

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