Implantable subcutaneous devices and methods employ a lead and/or electrode for cardiac monitoring and/or intervention. The devices and methods may employ one or more fixation elements including, for example, tines, tines with barbs, spring-loaded tines, flexible or collapsible tines, and other tined fixation mechanisms configured to passively secure one or both of the electrode or body of the lead in subcutaneous non-intrathoracic tissue. A method of implanting subcutaneous leads according to the present invention involves providing a lead comprising a lead body, an electrode, and one or more fixation elements, and passively securing one or both of the lead body and the electrode to subcutaneous non-intrathoracic tissue at one or more fixation sites using the fixation elements. The method may involve use of a delivery device, such as a sheath, for lead delivery to a subcutaneous non-intrathoracic implant site.