Greenbriar Sustainable Living Inc.: Exhibit 99.1

Scottsdale, Arizona, May 15, 2026 - Greenbriar Sustainable Living Inc. (TSXV: GRB) (OTC: GEBRF) ("Greenbriar" or the "Company") is pleased to announce that it has closed the non-brokered private placement (the "Private Placement") previously announced in its News Release dated May 11, 2026. The Private Placement comprises a total of 500,000 units (each, a "Unit") at CAD $0.45 per Unit for gross proceeds of CAD $225,000. Each Unit consists of one common share in the capital of the Company (each, a "Share") and one common share purchase warrant (each, a "Warrant") exercisable into one additional Share at a price of CAD $0.55 per Share until May 15, 2029.

No commissions or finder fees were payable in connection with the Private Placement. The proceeds from the Private Placement will be used for general working capital. The securities issued under the Private Placement are subject to a four month hold period that expires on September 16, 2026. The Private Placement remains subject to final approval of the TSX Venture Exchange.

Greenbriar is a leading developer of sustainable real estate and renewable energy. With long-term, high impact projects and led by a successful industry-recognized operating and development team, Greenbriar targets deep valued assets directed at accretive shareholder value.

Neither the TSX Venture Exchange nor its Regulation Service Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

This news release includes "forward-looking statements" and "forward-looking information" within the meaning of Canadian securities laws and United States securities laws (together, "forward-looking statements"). All statements included in this news release, other than statements of historical fact, are forward-looking statements including, without limitation, statements with respect to final TSXV approval, the issuance of Common Shares and Warrants and the approval by the TSX Venture Exchange. Forward-looking statements include predictions, projections and forecasts and are often, but not always, identified by the use of words such as "anticipate", "believe", "plan", "estimate", "expect", "potential", "target", "budget", "propose" and "intend" and statements that an event or result "may", "will", "should", "could" or "might" occur or be achieved and other similar expressions and includes the negatives thereof.

"Greenbriar Capital Corp. was recognized as a TSX Venture 50® company in 2014 and 2023.
TSX Venture 50 is a trade-mark of TSX Inc. and is used under license."

Toronto Venture Exchange Symbol: GRB | US OTC Symbol: GEBRF

- 2 -

Forward-looking statements are based on a number of assumptions and estimates that, while considered reasonable by management based on the business and markets in which the Company operates, are inherently subject to significant operational, economic, and competitive uncertainties, risks and contingencies. These include assumptions regarding, among other things: general business and economic conditions. There can be no assurance that forward-looking statements will prove to be accurate and actual results, and future events could differ materially from those anticipated in such statements. Important factors that could cause actual results to differ materially from the Company's expectations include those described under the heading "Risks and Uncertainties" in the Company's most recently filed MD&A (a copy of which is available under the Company's SEDAR profile at www.sedarplus.ca). The Company does not undertake to update or revise any forward-looking statements, except in accordance with applicable law.