Getty Images/Olivier Douliery
Anti-abortion activists hold a rally opposing federal funding for Planned Parenthood.
Republicans have worked tirelessly to defund the organization, which is the nation's largest abortion provider, since the 1970s. But prior to Pence's efforts, most of those battles had been fought on the state level.
If officially named as running mate, Pence's history of fighting abortion could boost Trump's standing as a conservative - the controversial billionaire has long struggled to win the support of the religious right.
That gives Pence a major advantage over other potential Trump picks - like retired Lt. Gen. Michael Flynn, who said he was pro-choice and earned dismay from many Republicans. He later waffled over his position on abortion rights.
But Pence has a consistent anti-abortion track record. In 2007, while serving in Congress, Pence sponsored an amendment to an appropriations bill that would have defunded Planned Parenthood by blocking it from receiving Title X grants.
The amendment didn't pass, but he pursued the issue for another four years before the House of Representatives finally approved an amendment to defund Planned Parenthood. That measure ultimately failed to become law - but not before it nearly shut down the federal government.
"What's clear to me, if you follow the money, you can actually take the funding supports out of abortion," he told Politico in 2011. "We then have a much better opportunity to move forward to be a society that says yes to life."
Planned Parenthood is prohibited from using federal money for abortions, but typically spends it on other women's health care services, like STD tests and exams to provide contraception. Pence argued that taking away federal funding from health clinics would limit their ability to perform abortions.
"We should end the day when the largest abortion provider is the largest recipient of [Title X] federal funding," he said.
The House has now voted eight times to defund Planned Parenthood. After an anti-abortion group last year released several videos claiming Planned Parenthood was involved in criminal activities, the debate over abortion has only grown more contentious.
Pence has also introduced several anti-abortion measures in his own state since becoming governor - including one this March that prohibits women from having abortions based on the disability status of the fetus, and mandated the cremation or burial of fetal tissue. The law was temporarily blocked by a federal judge following the Supreme Court's landmark abortion decision in June.
"Let the abortion providers provide for themselves," Pence told Politico. "I'd like to continue to be a persistent, respectful voice for the sanctity of life."