The mayor of San Antonio, Texas, Julian Castro, delivers his highly-anticipated keynote address Tuesday night at the Democratic Party's presidential nominating convention.

The 37-year-old Castro is the Democratic National Convention's first Latino keynote speaker. As mayor of the nation's seventh-largest city, he is also the youngest mayor of a top 50 U.S. city. Last year, he won re-election with more than 80 percent of the vote.

This marks Castro's first time in the national spotlight, in what Democrats hope will be a moment similar to President Barack Obama's breakout keynote speech at the 2004 convention. The speech catapulted Mr. Obama, then just a little-known state senator, to national prominence and set the stage for his presidential bid.

Some have even speculated that Castro could one day become the nation's first Hispanic president.

The San Antonio mayor shares a similar background with President Obama as a graduate of Harvard Law School and the son of a single mother. Castro's twin brother, Joaquin, a Texas state representative expected to win election to Congress in November, will introduce his brother at the convention Tuesday night.

Born in San Antonio in 1974, the Castro brothers got their first taste of politics as children, through their mother, Rosie, an activist who campaigned for Mexican-American civil rights.

Castro's selection as keynote speaker is widely seen as part of President Obama's effort to boost support for his re-election among Hispanics, the nation's largest minority group and a key voting bloc in this year's race.