About Jeffrey Sack Law

Jeffrey Sack Law is a solo Toronto practice built around labour law, run by Jeffrey Sack, K.C. from an office on Yonge Street in midtown Toronto. Sack's practice centres on unions and professional associations rather than individual employees, and it spans litigation, collective bargaining, and interest arbitration. Sack was a co-founder of Sack Goldblatt Mitchell, a Toronto labour firm started in the mid-1970s that grew into a major union-side practice before becoming Goldblatt Partners LLP.

As a litigator, Sack argued the Lavigne case at the Supreme Court of Canada, which upheld the constitutional validity of the Rand formula and confirmed unions' right to direct dues toward political activities. Sack also argued the first case to uphold the right to strike under the Canadian Charter of Rights and Freedoms. On the negotiating side, Sack has bargained with government on behalf of physicians and with hospitals on behalf of medical residents, and has sat as a union nominee on interest arbitration boards for firefighters, police officers, faculty, and health care support staff.

Milestones & recognition

  • Co-founded Sack Goldblatt Mitchell in the mid-1970s, a Toronto labour firm that grew to represent major unions before it became Goldblatt Partners LLP.
  • Argued the Lavigne case at the Supreme Court of Canada, upholding the constitutional validity of the Rand (agency) formula.
  • Argued the first case to uphold the right to strike under the Canadian Charter of Rights and Freedoms.
  • Received the Gerard Dion Award from the Canadian Industrial Relations Association for contributions to Canadian labour law.
  • Received the Outstanding Practitioner Award from the U.S. Labor and Employment Relations Association in 2008.
  • Received the Bora Laskin Award from the University of Toronto's Centre for Industrial Relations and Human Resources.
  • Author of Winning Cases at Grievance Arbitration, published by Lancaster House in 1993.

In the community

  • Teaches international labour law as an adjunct professor at the University of Toronto.
  • Serves as Associate Editor of the Canadian Labour and Employment Law Journal.

The neighbourhood

The office sits on Yonge Street in Davisville Village, a midtown Toronto neighbourhood that runs between St. Clair and Eglinton avenues. It's a corridor of office buildings mixed with apartment and condo towers, anchored by the Davisville subway station on Line 1, which makes the office an easy transit trip for clients and union representatives coming from across the city.

Frequently asked questions

Does Jeffrey Sack Law represent individual employees, or only unions?
The practice centres on representing unions and professional associations, including in interest arbitration and collective bargaining, rather than taking on individual employee claims.
What is interest arbitration, and does the firm handle it?
Interest arbitration sets the terms of a new collective agreement when a union and employer can't reach one through bargaining. Jeffrey Sack sits as a union nominee on interest arbitration boards and has represented firefighters, police officers, faculty, and health care support staff in that role.
Has the firm argued cases at the Supreme Court of Canada?
Yes. Jeffrey Sack argued the Lavigne case, which upheld the constitutional validity of the Rand formula, and argued the first case to uphold the right to strike under the Canadian Charter of Rights and Freedoms.
Does Jeffrey Sack teach or write about labour law?
Yes. Sack teaches international labour law as an adjunct professor at the University of Toronto, serves as Associate Editor of the Canadian Labour and Employment Law Journal, and wrote Winning Cases at Grievance Arbitration, published by Lancaster House.
Where is the office located?
The office is at 1881 Yonge Street, Suite 500, in Toronto's Davisville Village neighbourhood, close to the Davisville subway station.
How can I reach the firm?
The office can be reached at (416) 271-4003 or by email at jsack@jeffreysacklaw.com.

Where to find them

1881 Yonge Street, Suite 500, Toronto, Ontario M4S 3C4 · 416-271-4003

Similar firms in City of Toronto

KZP Law

1 lawyer

KZP Law is a Toronto practice led by lawyer Karen Zvulony, focusing on employment law, assessment law (legal fee disputes under the Solicitors Act), and civil litigation. Karen has more than 19 years of experience and…

Employment & Labour LawEmployment & Labour LawCivil Litigation & Dispute ResolutionCivil Litigation & Dispute Resolution

Skupsky Law serves Toronto, the GTA, and the Georgian Bay area from offices in Toronto, Collingwood, and Oakville. It handles employment and sexual harassment law, equine and equestrian matters, insurance disputes, pr…

Employment & Labour LawEmployment & Labour LawInsurance LawInsurance LawCivil Litigation & Dispute ResolutionCivil Litigation & Dispute ResolutionAdministrative & Regulatory LawAdministrative & Regulatory Law

This solo Toronto, Ontario practice focuses on employment, consumer, injured worker, and disability rights matters. It offers a free initial consultation and, in some cases, will represent clients at no cost.

Employment & Labour LawEmployment & Labour LawCriminal DefenceCriminal Defence

Listing compiled from the firm’s public website in August 2026. Verify licence status in the Law Society of Ontario directory ↗