The incident happened in Alabama during a Sunday church service yesterday and has left the community in shock.
Witnesses described how suspect James Minter entered the church, sitting in the front row between his girlfriend and baby.
According to a police statement, he then pulled out a handgun and shot the woman in the face and shoulder, also hitting their 1-month-old son the hand.
When the pastor intervened he was shot in the leg, before members of the congregation managed to wrestle away his gun.
Minter managed to escape from church, but was later arrested.
All of the victims are in a stable condition.
Minter has been charged with three counts of attempted murder and is being held without bond at the Dallas County jail.