Mr. Gastélum was admitted to practice in California and U.S. District Court for the Central District of California in 1999. In 2003 he was admitted to U.S. Court of Appeals, Fifth Circuit, and in 2006 to the U.S. District Court for the Eastern District of California and U.S. Court of Appeals, Ninth Circuit. He has been admitted pro hac vice in states including Arizona, Texas, New York, Washington and West Virginia.

Represented former bank president to obtain insurance coverage for defense expenses incurred in relation to investigation of the bank, while the holding company was in bankruptcy.

Sued on behalf of policyholder landowner in United States District Court and represented client in the Ninth Circuit Court of Appeals to obtain payment for business interruption caused by damage to and blockage of a waterway used by the policyholder's tenants.

Represented former director of organization accused of criminal securities violations, obtaining payment from both insurers and the former employer, pursuant to indemnity and insurance agreements, for defense resulting in dismissal from the indictment.

Defended trade organization against claims in Federal court that it failed to provide promised insurance to a member injured in a horse racing accident in West Virginia. Claims were for in excess of $10 million. Obtained insurance coverage for co-defendants, existence of which had initially been denied, and settled with those funds.

Represented high profile religious institutions in disputes with insurers over defense and indemnity for allegations of improper actions by their employees.

Represented prime contractor for the Space Shuttle and International Space Station, in an action brought by American Home Assurance Company and National Union Fire Insurance Company of Pittsburgh, PA to establish insurance coverage for claims related to the termination of a subcontractor. The case was tried successfully to a multimillion-dollar jury verdict and argued successfully to the Fifth Circuit.

Obtained insurance coverage benefits for securities firm with respect to claims against broker-dealer regarding independent actions of registered representatives.