[3] In 2021, Walker was one of the first international journalists to arrive in Kabul after the Taliban took over, producing a documentary "Return of the Taliban" for Vice that won "Best News Coverage: Long Form" at the 43rd News and Documentary Emmy Awards.

First based at Al Jazeera English's main US bureau in Washington, D.C. and then in Al Jazeera America's San Francisco Fault Lines show hub, he was a presenter on Fault Lines, the channel's flagship news magazine about the Americas, and reported from across the continent.

[10] Walker won a DuPont-Columbia University Award in Broadcast Journalism for his work in Haiti.

[13] Walker has also repeatedly covered the Occupy movement in the US and the shooting of Michael Brown near St. Louis, Missouri, which precipitated sustained protests.

[citation needed] Walker has worked for the Baghdad Bulletin,[14] and various international news organisations, including Reuters[15] and AFP, and has reported from a number of key countries around the Middle East region, including: Iraq,[16][17] Libya, and Afghanistan.