After going undrafted in the 2016 NFL draft, he was signed by the New England Patriots as a rookie free agent.

On September 3, 2016, he was released by the Patriots as part of their final roster cuts with a designation to be added to injured reserve.

[4] On December 11, 2016, LeBlanc recorded his first career interception against the Detroit Lions, picking off Matthew Stafford and returning it for a touchdown.

[11] LeBlanc was forced into action in Week 11 during a 48–7 loss to the New Orleans Saints following a litany of injuries in the Eagles' secondary.

In an interview with the media following a 16–15 win against the Chicago Bears in the playoffs, LeBlanc was praised by defensive coordinator Jim Schwartz, saying, "I don’t know where we’d be without Cre’Von ... that might have been the key to our season, putting the waiver claim in.

[13] LeBlanc signed a one-year extension with the team on September 2, 2019, and subsequently placed on injured reserve with a foot injury suffered during training camp.

[17] LeBlanc started the Eagles' Wild Card game against the Seattle Seahawks, where he recorded four tackles and two pass deflections in the 17-9 loss.