Atty. William Daniel Marsillo

Atty. William Daniel Marsillo

William Daniel Marsillo is a lawyer practicing commercial, litigation. William received a B.S.E. degree from Stevens Institute of Technology in 1994, and has been licensed for 28 years.

Armonk Armonk 28 yrs experience 28 year
Call (551) 444-4076 Book Appointment

Profile Summary

About William Daniel Marsillo at a glance

William Daniel Marsillo is a Partner based in Armonk, New York, practicing at Boies, Schiller & Flexner LLP. They have 28+ years of legal experience, licensed to practice since 1998. Their practice focuses on business and litigation. Admitted to practice in New York (1998). Educated at Harvard Law School (J.D., 1997) and Stevens Institute of Technology (B.S.E. Materials, 1994). Serands clients in Armonk, NY and the surrounding metropolitan area.

Verified attorney profile · Updated June 2026

About

  • William Daniel Marsillo is a lawyer practicing commercial, litigation
  • William received a B.S.E. degree from Stevens Institute of Technology in 1994, and has been licensed for 28 years
  • William practices at Boies, Schiller & Flexner LLP in Armonk, NY

Practice Areas Explained

William Daniel Marsillo's Areas of Practice

Each practice area below reflects the types of cases William Daniel Marsillo handles, with a brief overview of what that area of law covers.

Business & Corporate Law

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

William Daniel Marsillo is one of 501,317 business attorneys indexed nationally. Browse business attorneys in New York →

Civil Litigation

Civil litigation attorneys for breach of contract, business disputes, civil rights, and class action lawsuits.

William Daniel Marsillo is one of 454,532 litigation attorneys indexed nationally. Browse litigation attorneys in New York →

Jurisdictional Context

Why local counsel matters in New York

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

Looking for additional New York attorneys? Browse all attorneys in Armonk or all attorneys in New York.

Frequently Asked

Common questions about William Daniel Marsillo

Where is William Daniel Marsillo's law office located?
William Daniel Marsillo's law practice is located in Armonk, New York. The firm is Boies, Schiller & Flexner LLP. You can contact the office directly through this profile page.
What practice areas does William Daniel Marsillo handle?
William Daniel Marsillo focuses on business, litigation. Each practice area listed reflects experience handling cases of that type in New York.
How long has William Daniel Marsillo practiced law?
William Daniel Marsillo has 28+ years of legal experience and has been licensed since 1998.
Where did William Daniel Marsillo go to law school?
William Daniel Marsillo earned their education at (J.D., 1997); (B.S.E. Materials, 1994).
How can I contact William Daniel Marsillo for a consultation?
You can contact William Daniel Marsillo 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.

Practice Areas

Education

J.D.
Harvard Law School
- 1997
B.S.E. Materials
Stevens Institute of Technology
- 1994

Bar Admissions

New York
Admitted: 1998

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