Samuel's baptism took place in Garner's family church, Christ Church United Methodist.
The whole weekend was a celebration, as couple had their eighth wedding anniversary Saturday. Affleck and Garner kept it low-key at their favorite local hangout Pies & Pints, where they shared pizza and beer.
The pair followed up with dessert at Ellen's Homemade Ice Cream, where Affleck reportedly tipped several employees $100 apiece.
Sunday morning, Affleck and Garner took Samuel and with older sisters Violet, 7, and Seraphina, 4, to the church, where they were joined by family and friends to bless the baptism.