Exhibit 5.1

May 26, 2026

Callan JMB Inc.

244 Flightline Drive, Spring Branch,

Texas 78070-6241

Re: Callan JMB Inc. - Form S-8 Registration Statement

Ladies and Gentlemen:

We refer to the above-captioned registration statement on Form S-8 (the “Registration Statement”) under the Securities Act of 1933, as amended (the “Act”), filed by Callan JMB Inc., a Nevada corporation (the “Company”), with the Securities and Exchange Commission (the “Commission”).

We have examined the originals, photocopies, certified copies or other evidence of such records of the Company, certificates of officers of the Company and public officials, and other documents as we have deemed relevant and necessary as a basis for the opinion hereinafter expressed. In such examination, we have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as certified copies or photocopies and the authenticity of the originals of such latter documents.

Based on our examination mentioned above, we are of the opinion that the securities being issued pursuant to the Registration Statement, when so issued, are legally and validly issued fully paid and non-assessable.

We express no opinion herein as to the laws of any state or jurisdiction (including the statutory provisions and all applicable judicial decisions interpreting those laws) other than the State of Nevada and the federal laws of the United States of America.

We hereby consent to the filing of this opinion as Exhibit 5.1 to the Registration Statement. We also hereby consent to the reference to our firm under the caption “Legal Matters” in the Prospectus. In giving the foregoing consent, we do not hereby admit that we are in the category of persons whose consent is required under Section 7 of the Act, or the rules and regulations of the Commission. This opinion is expressed as of the date hereof unless otherwise expressly stated, and we disclaim any undertaking to advise you of any subsequent changes in the facts stated or assumed herein or of any subsequent changes in applicable laws.

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