Aims to be the first Latino U.S. President

Former Mayor of San Antonio, Texas and Barack Obama-era Cabinet member Julian Castro is set to launch his bid to become the nation’s first Hispanic President.

Mr. Castro, 44, would be among the underdogs in a political showdown that may well feature heavyweights like former Vice-President Joe Biden; U.S. Senators Elizabeth Warren, Bernie Sanders, Kamala Harris and Kirsten Gillibrand; and perhaps even billionaire businessman Michael Bloomberg.

He would also become the third prominent Latino presidential candidate in four years, after Republican Senators Ted Cruz and Marco Rubio fought Donald Trump for their party’s nomination in 2016. Mr. Castro’s candidacy could also help revive Democratic enthusiasm among Latino voters, who supported Hillary Clinton but at a lower rate than Mr. Obama.

His national profile took off in 2012 when he became the first Latino to give a keynote address at the Democratic National Convention. Four years later, he was a finalist to be Ms. Clinton’s running mate. “I’ll tell you and I’ll tell the world what I’m going to do,” Mr. Castro, a fierce Trump critic, said this week on MSNBC.