The two went to an outdoor mass together Sunday at the Italian Heritage Festival in Clarksburg.
Maloney attends the nondenominational Chestnut Ridge Church in Morgantown but was raised and confirmed as a Catholic, campaign spokesman Kent Sholars said.
The campaign has sought to highlight that Maloney is a member of Chestnut Ridge, a fact that was noted in one of his campaign ads last year.
Renzelli said he was part of the "Democrats for Underwood" group in 1996 that helped Underwood defeat Democrat Charlotte Pritt.
The Tomblin campaign said it, too, has support from members of both parties. In 2011, for instance, Charleston Mayor Danny Jones, a Republican, appeared in a Tomblin ad.
"Democrats, Republicans, independents and, in fact, according to the West Virginia Poll, the majority of West Virginians, support Gov. Tomblin," Tomblin campaign spokesman Chris Stadelman said. "He appreciates their support."