The Ethan Allen, together with the George Washington, Lafayette, James Madison, and Benjamin Franklin classes comprised the "41 for Freedom" that were the Navy's main contribution to the nuclear deterrent force through the late 1980s.

Rather than being designed as Skipjack-class attack submarines with a missile compartment added, the Ethan Allens were the first submarines designed "from the keel up" as Fleet Ballistic Missile (FBM) submarines carrying the Polaris A-2 missile.

They were functionally similar to the George Washingtons, but longer and more streamlined and with torpedo tubes reduced to four.

To comply with SALT II treaty limitations as the Ohio-class ballistic missile submarines entered service, in the early 1980s the Ethan Allens were refitted and officially designated SSNs (fast attack submarines), but often referred to as a "slow approach".

Sam Houston and John Marshall were further converted to carry SEALs or other Special Operations Forces, accommodating 67 troops each with dry deck shelters to accommodate SEAL Delivery Vehicles or other equipment.