Washington: Presumptive Republican US Presidential nominee Donald Trump said on Saturday he chose Indiana Governor Mike Pence as his running mate to boost party unity. "One of the biggest reasons I've chosen Mike, one of the reasons is party unity, I have to be honest," Xinhua news agency quoted Trump as saying at a rally in New York. Calling Pence his "first choice" as the running mate, Trump also touted Pence's job-creating credentials. "This is the primary reason I wanted Mike -- other than that he looks very good, other than he's got an incredible family, and incredible wife," said Trump. The pick of Pence as running mate came as Trump was scrambling to solidify the Republican base and win support from social conservatives. Pence, 57, was a Republican lawmaker for 12 years and the third-highest-ranking member of the GOP in the House before becoming the Governor of Indiana in 2013. During his stint in Congress, he was assigned to the Foreign Affairs Committee, a credential which could make up for Trump's lack of foreign affairs experience in a competitive general election with former US Secretary of State Hillary Clinton as the standard-bearer of the Democratic Party. Once calling himself as "a Christian, a conservative and a Republican, in that order", Pence is also a beloved social conservative among the devout evangelical conservatives within the party. Therefore, Trump's pick of Pence would also help to quell concerns among social conservatives that the New York billionaire developer is too liberal on social issues. However, the two differ on a range of issues crucial to Trump's candidacy. During the primary season, Pence endorsed Trump's rival Senator Ted Cruz of Texas, and was once a vocal critic of Trump's proposal for a temporary ban on Muslim entering the country. Pence also joined US President Barack Obama and House Speaker Paul Ryan to back the Trans-pacific partnership deal, a trade deal staunchly opposed by Trump.