[7] On January 20, 2017, Walker assumed the role of acting Commanding General, District of Columbia Army and Air National Guard, nicknamed the “Capitol Guardians”.

Pelosi administered the Oath of Office to Walker during a House pro forma session on April 26,[3] hours prior to President Biden's address to Congress.

[19] Walker is the former vice chairman, board of directors of the Young Marines, a military affiliated nonprofit service organization for boys and girls ages eight through high school that provides developmental programs that nurtures and encourages its over 10,000 members into becoming responsible citizens who enjoy a positive and drug-free lifestyle.

Walker retired as a Special Agent of the U.S. Drug Enforcement Administration (DEA) in 2014 with thirty years of distinguished service in positions of increasing responsibility.

[20][21] As Deputy Director of the NIC-C, Walker led intelligence officers in the day-to-day operations of an IC mission support activity.

Prior to this assignment he served as the Director and Deputy Assistant Administrator, DEA Office of Chemical and Pharmaceutical Diversion Control.

In this position, Walker strengthened relationships with international partners and led delegations to Austria and Belgium to win support for global pharmaceutical and chemical compliance initiatives.

[22] While assigned to DEA New York, Walker expanded and reinforced relationships with foreign counterparts having shared counter narcotics responsibilities and led multi-agency delegations to China, Hong Kong and Thailand to collaborate on international heroin investigations and subjects of common interests in Asia.

Walker served as a criminal investigator in the DEA Chicago, New York and Miami Field Divisions and as a Narcotics Attaché in two foreign diplomatic posts.

During his career, Walker, a Spanish speaker, traveled to numerous countries to join forces with intelligence and law enforcement partners having shared interests and mutual concerns.

[23][24][25] [4] Walker concurrently served as the Director of the District of Columbia National Guard (DCNG) and was a member of the Headquarters Department of the Army Senior Executive Service.