Castro gained national attention in 2012 when he was the first Hispanic to deliver the keynote address at a Democratic National Convention in Charlotte , North Carolina . Following the 2012 elections , Castro declined the position of United States Secretary of Transportation , partly with an eye on running for governor of Texas after 2017 . However , in 2014 , Castro accepted President Barack Obama 's offer of the position of United States Secretary of Housing and Urban Development . Castro resigned as mayor effective July 22 , 2014 , so that he could take up his duties in Washington . The San Antonio City Council elected councilmember Ivy Taylor to replace him
Democratic National Convention
2012 Democratic National Convention
Julian Castro