Can a lawyer represent a new client in a suit brought by a former client when the new suit is unrelated to the prior work?

Plain-English summary

A lawyer had represented client A in a tenant-eviction matter that ended in a final judgment. Later, client B asked the lawyer to defend a suit that A had brought against B, the suit being unrelated to the lawyer's original representation of A and having been filed by a different attorney. The lawyer asked whether a conflict of interest barred the new representation.

Applying DR 5-105, the committee concluded that representing B would not impair the attorney's independent professional judgment, so the lawyer could ethically handle B's litigation. It emphasized that the attorney had a responsibility not to reveal to B, or use in representing B, anything he had learned from A during the original attorney-client relationship, and that this limit should be clearly explained to B at the initial stage of the new relationship.

Currency note

This opinion was issued in 1970, before The Florida Bar's adoption of the 2006 revisions to the Rules of Professional Conduct. It applied the former Code of Professional Responsibility (DR 5-105), the subject matter of which (duties to former clients) is now addressed by Rule 4-1.9. Treat this page as historical context, not current guidance. Verify against the current rules before relying on any specific requirement mentioned here.

Common questions

Q: Can a lawyer take a case against a former client?

A: Under this opinion, yes, where the new matter is unrelated to the former representation and the lawyer uses no information learned from the former client.

Q: What duty survives the former representation?

A: The opinion holds the lawyer may not reveal to or use for the new client anything learned from the former client, and must explain that limit to the new client at the outset.

Background and rules framework

The opinion applied DR 5-105 of the former Code of Professional Responsibility, addressing conflicts that could impair independent professional judgment. The duties to former clients are now addressed by Rule 4-1.9. The Model Rule analogue is Rule 1.9.

Citations and references

Rules of Professional Conduct:

• DR 5-105 [Code of Professional Responsibility; former-client subject matter now in Rule 4-1.9]

See also

• FL Bar Ethics Op. 71-18: Suing an Unrelated Former Client
• FL Bar Ethics Op. 70-57: Withdrawing to Represent One Client Against Another
• FL Bar Ethics Op. 71-14: Government Lawyer Adverse to a Former Private Client

Source

• Landing page: https://www.floridabar.org/etopinions/etopinion-70-52/
• Original PDF: https://www-media.floridabar.org/uploads/2017/04/FL-Bar-Ethics-Op-70-52-1.pdf

Original opinion text

Reproduced from the official source for research purposes. The linked source is authoritative.

FLORIDA BAR ETHICS OPINION
OPINION 70-52
November 23, 1970
Advisory ethics opinions are not binding.
An attorney may represent a client in an action against a former client if the matter in litigation is not related to the attorney's representation of the former client. In representing the new client the attorney may not use any information obtained through representation of his former client.
CPR: DR 5-105
Chairman Massey stated the opinion of the committee:
A member of The Florida Bar inquires of a possibility of a conflict of interest which essentially involves the following background. The attorney represented A, a client, in a tenant eviction matter, terminating the same with a final judgment. Thereafter, B, a client, sought the attorney's representation to defend a suit brought by A against B, the suit being unrelated to the original representation of A by the attorney and having been instituted by a different attorney.
This inquiry relates to the criteria set forth in CPR DR 5-105. It is the Committee's opinion that the proposed representation of B would not impair the attorney's independent professional judgment and, therefore, the attorney may ethically handle B's litigation. Certainly, the attorney has the responsibility of not revealing to B or using in the course of representing B anything he may have learned from A during the original attorney-client relationship, and this should be clearly explained to B in the initial stage of the new attorney-client relationship.