Dallas County Sheriff Lupe Valdez announced Wednesday she’s running as a Democrat for Texas governor, joining an already crowded field of contenders lined up to challenge Republican Gov. Greg Abbott in 2018.

Here's a closer look at Valdez, the first openly gay, Hispanic sheriff in the country — and the Democratic party's highest-profile contender for the state's top slot.

Childhood and education

Valdez was born in San Antonio in 1947, one of eight children in a family of migrant farm workers. She earned a bachelor’s degree in business administration from Southern Nazarene University — a liberal arts college in Bethany, Oklahoma — before receiving a master’s in criminology and criminal justice from the University of Texas at Arlington.

Criminal justice career

After attaining the rank of captain in the U.S. Army, Valdez went on to work as a federal agent for U.S. Customs and Border Protection and, later, the Department of Homeland Security, focusing on fraud and drug cases for almost 30 years before being elected sheriff of Dallas County, the state’s second most populous county.

Dallas County sheriff

Valdez is currently serving her fourth term as Dallas County sheriff, and she drew national headlines when she was first elected in 2004 as the nation's first openly gay Hispanic sheriff. Her office oversees the second largest county jail in Texas.

In 2015, Valdez got crosswise with Abbott when she announced her department would decide whether to turn over undocumented offenders to federal immigration authorities on a case-by-case basis. That move prompted Abbott to warn Valdez in a letter that Texas sheriffs who did not cooperate with federal "detainers" would face losing state grant money. The debate resurfaced in 2017, and was ultimately the driving force behind the anti-“sanctuary cities” and immigration enforcement bill Abbott signed into law earlier this year.

Valdez's office has also faced criticism over an alleged lack of transparency around prisoner deaths and injuries. After the brutal death of a prisoner at the county jail in December 2016, the Dallas Morning News' editorial board knocked the sheriff for "pitiful reasoning" and being slow to recognize the severity of the incident.

From sheriff to gubernatorial candidate

Valdez announced her campaign for governor in Austin on Wednesday, telling reporters that she had submitted her resignation as sheriff.

Dallas County Administrator Darryl Martin told The Texas Tribune on Wednesday that Valdez is required under the Texas Constitution to continue serving in her capacity until a successor is sworn in. County commissioners are scheduled to meet Dec. 19 to name Valdez's replacement.

Once that happens, she will officially join the other six Democrats who have already launched bids for the party’s gubernatorial nomination. Andrew White, son of late Gov. Mark White, is expected to throw his hat into the ring — marking the eighth Democrat to enter the race — on Thursday in Houston.