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Cassidy O'Sullivan, Business Attorney in Los Angeles, California

focused on Business and Litigation

Hueston Hennigan Llp

Los Angeles, CA

Trusted business attorney serving Los Angeles.

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Quick answer

Cassidy O'Sullivan is an attorney based in Los Angeles, CALIFORNIA. The practice focuses on Business and Litigation. Currently practicing at Hueston Hennigan Llp.

Based in
Los Angeles, CALIFORNIA
Experience
attorney
Known for
Business · Litigation
  • Handles Business and Litigation matters from Los Angeles, CALIFORNIA.
  • Recognized with Best Lawyers in America — Commercial Litigation (2026).

About Cassidy O'Sullivan: Cassidy O'Sullivan is an attorney based in Los Angeles, CALIFORNIA. The practice focuses on Business and Litigation. Currently practicing at Hueston Hennigan Llp.

Areas of practice

Practice areas handled by Cassidy O'Sullivan

Cassidy concentrates on business and litigation. Each area below outlines the kind of case Cassidy handles, typical outcomes to expect, and how the intake process starts.

Business cases in Los Angeles, California

Cassidy takes business matters in Los Angeles, California. Typical engagements include intake calls to scope the issue, review of any records or filings you already have, and a written strategy memo before Cassidy agrees to represent you.

Litigation cases in Los Angeles, California

Cassidy takes litigation matters in Los Angeles, California. Typical engagements include intake calls to scope the issue, review of any records or filings you already have, and a written strategy memo before Cassidy agrees to represent you.

Biography

About Cassidy O'Sullivan — Attorney of California business experience

Cassidy O'Sullivan is an attorney based in Los Angeles, CALIFORNIA. The practice focuses on Business and Litigation. Currently practicing at Hueston Hennigan Llp.

Cassidy O'Sullivan is a top attorney recognized by Best Lawyers in the practice area(s) of Commercial Litigation.

Cassidy, who practices law in Los Angeles, California, has been recognized since 2026. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Cassidy is held by other top lawyers in the same geographic and legal practice area.

Working with Cassidy on a business matter

Cassidy O'Sullivan is a top attorney recognized by Best Lawyers in the practice area(s) of Commercial Litigation. Cassidy, who practices law in Los Angeles, California, has been recognized since 2026. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Cassidy is held by other top lawyers in the same geographic and legal practice area.

Clients Cassidy works with

Cassidy reviews new inquiries case-by-case for business and litigation matters in Los Angeles and the surrounding California area.

Credentials

Cassidy O'Sullivan's legal education and bar admissions

  • New York University

    J.D. · 2021

Cassidy studied at J.D. in New York University.

Law school and academic background

Cassidy completed J.D. in New York University. Formal legal training is one signal of substantive knowledge — the day-to-day practice Cassidy runs in California is where that training gets applied to real client questions.

Recognition

Awards, publications, and recognition of Cassidy O'Sullivan

Cassidy has received 1 formal recognition from bar associations, industry bodies, and peer-review services.

  • Best Lawyers in America — Commercial Litigation

    2026

Legal awards and honors

Best Lawyers in America — Commercial Litigation (2026).

Locations

Cassidy O'Sullivan's office in Los Angeles

Cassidy's primary office is at 523 West Sixth Street, Suite 400, Los Angeles, California, 90014. In-person meetings are by appointment; a phone intake usually comes first.

Main office

Hueston Hennigan Llp

523 West Sixth Street, Suite 400

Los Angeles, California 90014

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Client feedback

Client reviews of Cassidy O'Sullivan

Cassidy has not yet collected verified client reviews on LawyersListed. Reviews here are all from confirmed clients; anonymous ratings are moderated out.

No reviews yet

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Hiring guide

How to hire Cassidy O'Sullivan — what to expect in your first consultation

Working with a new business attorney should feel structured. Here's how the first two conversations with Cassidy usually go, from the moment you request a consult to the day representation begins.

Consultation formats and pricing

Cassidy charges for the initial consult. That fee is credited toward representation if you retain Cassidy's office.

What to bring to your first meeting

Bring any documents you already have — police reports, medical records, filed pleadings, correspondence from an insurer, a copy of the contract at issue. If you're not sure, err on the side of bringing everything; Cassidy will tell you what matters and what doesn't.

Questions to ask a business attorney in Los Angeles, California

A short list to run through before you commit: How many business matters have you handled in the last year? What's your fee structure? Who else in the office will work on this? What's your realistic estimate of timeline and range of outcomes? How do I reach you between meetings?

Fees & payment

Fees, payment methods, and consultation options for Cassidy

Cassidy discusses fees during intake so the arrangement fits the matter. Contingency, hourly, and flat-fee options are all common in business practice — ask which fits.

Hourly rates, contingency fees, and flat-fee options

Every business matter is priced differently. Simple document review might be a flat fee. Injury litigation is often contingency. Complex commercial disputes usually run hourly with a retainer. Cassidy confirms the model in the engagement letter before any work starts.

Payment methods and payment plans

Cassidy's office accepts standard payment methods. Ask about payment plans if the retainer is a stretch — many business practices work with clients on structured schedules.

Frequently asked

Frequently asked questions about Cassidy O'Sullivan

  • How much does it cost to hire Cassidy for a business case?

    Cost depends on the type of matter, the fee model (contingency, flat, hourly), and how contested the case becomes. Cassidy walks through the likely range during the consult so there are no surprises.

  • Does Cassidy offer a free consultation?

    Cassidy charges for the initial consult; that fee is credited toward representation if you retain Cassidy's office. Some business attorneys offer free consults — check Cassidy's current terms during booking.

  • How long do business cases in California typically take?

    Simple business matters can wrap in a few weeks; disputed cases can run 6–18 months from intake to resolution, longer if the matter goes to trial. Cassidy gives a realistic estimate for your facts at the consult — vague answers here are a red flag.

  • Can Cassidy take my case if I'm outside Los Angeles?

    Cassidy is licensed in California. Matters governed by California law are the natural fit. Out-of-state matters are handled case-by-case, sometimes with local co-counsel. Ask during intake — Cassidy will tell you if the case is a fit or refer you to someone closer to your court.

  • What should I bring to my first meeting with Cassidy?

    Bring every document that touches the dispute: contracts, correspondence, police or medical reports, filed pleadings, invoices, photographs, insurance letters. Also bring a written timeline of what happened, in your own words. Cassidy will filter what matters — over-preparing at intake is always cheaper than needing a second meeting.

  • Is Cassidy accepting new business clients right now?

    Cassidy's intake status shifts week to week. Submit the form; the office will confirm availability or refer the matter out.

Areas served

Business attorneys serving Los Angeles, San Francisco and San Diego in California

Cassidy handles business matters throughout California. Each city below is a direct link into the search page for verified business attorneys in that community.

More counsel

If Cassidy's intake is full or the fit isn't right, these business attorneys in Los Angeles handle similar matters. Every profile below is verified and open to consultations.