Pence, who unlike his boss is not independently wealthy, could possibly use funds from the Trump-Pence re-election campaign or from Pence's new PAC, which is hosting a fundraiser Friday, to pay Richard Cullen, the chairman of McGuireWoods LLP.
Pence told reporters in Miami Friday that hiring an outside lawyer was standard practice.
"It's very routine," Pence said. "Very routine."
The legal fees will be paid through "non-taxpayer funds," a Pence adviser told CNN Thursday, declining to elaborate whether that meant it would come out of Pence's pockets.
The Federal Election Commission prohibits individuals from using campaign funds for personal use, but legal services sparked by an officeholder's official work could be deemed appropriate, according to FEC regulations.
"The Commission decides on a case-by-case basis whether legal expenses are considered 'personal use' and thus are expenses that a candidate may not pay for using campaign funds," FEC guidelines read.
"In several advisory opinions the Commission has said that campaign funds may be used to pay for up to 100% of legal expenses related to campaign or officeholder activity, where such expenses would not have occurred had the individual not been a candidate or officeholder."
The operating question for both Pence and Trump, who similarly has hired a private lawyer: Would the two Republicans need to retain counsel if they had not run in or won the 2016 election?
Another option could be the vice president's new leadership PAC, the Great America Committee, which is hosting a fundraising event Friday night in Indianapolis. Pence could also theoretically tap a fund organized by the Republican National Committee.
Two Washington campaign finance lawyers said the rules offer leeway when hiring outside legal representation.
Bob Bauer, a Democratic lawyer whose practice includes advising clients on campaign finance issues, told CNN it would raise concerns if Pence used his leadership PAC to pay his legal fees.
"It is a problem if a committee is formed and money raised for the expressed purpose of supporting candidates and normal political activities," Bauer said, "but the intention is in fact to establish a personal legal expense fund."