Subcutaneous systems and leads may be fixed in tissue after placement by use of one or more expanding fixation elements. An expanding fixation element is provided on an implantable lead and configured to secure one or both of a subcutaneous electrode and the lead body within subcutaneous non-intrathoracic tissue. A delivery apparatus comprising a sheath may be included that is configured to introduce the lead to a desired subcutaneous non-intrathoracic location within the patient. A method of lead delivery typically involves introducing a sheath into a subcutaneous non-intrathoracic body location of a patient, providing a lead comprising a lead body and an electrode, and advancing the lead through the sheath and to the subcutaneous non-intrathoracic body location. The method further involves fixing the lead to subcutaneous non-intrathoracic tissue using an expanding fixation element and thereafter removing the sheath from the patient.