Mr. Jackson was the chief of security for the Regents seen in "The 40th Floor". He was unhappy that his guards in the building were stunned by the Warehouse agents. He was skeptical that Sally Stukowski posed a serious threat to the Regents, because the site had only been chosen three hours prior to the meeting. After the elevator was compromised, he actively assisted Artie and Myka, until he sacrificed himself so everyone else would escape the disintegrating staircase. His final instructions to Myka were to protect the Regents at any cost, which she managed.

Wikia W13 - Mr. Jackson's sacrifice

Jackson's final moments