Karen McCafferty was born on the 7th January 2239 to Christine Phillips and Paul McCafferty, in the city of Portsmouth, England, Great Britain, European Hegemony, Earth, Sol, United Federation of Planets. She is the couple's only child, though as she was growing up she often expressed a desire to have a little brother to take care of and play with.
Living in the traditional heart of Great Britain's Royal Navy, Karen was influenced from an early age by the romance of the sea and the part the Royal Navy had played in the history of her home country and the Earth. It was from these tours of historical exhibits -- including Admiral Horatio Nelson's still-preserved flagship at the Battle of Trafalgar, H.M.S. Victory -- that Karen's interest in service to a higher purpose and noble ideas took root.
Karen qualified for and enrolled in Starfleet Academy's San Franscisco, Earth campus on 1st July 2256, taking a specialisation of Astronavigation but with the goal of entering the Command Track training program. At the end of her first year, Karen successfully qualified for this and was accepted into it for her second year. During her second year, Karen demonstrated an aptitude for leadership and great tactical acumen. Scoring high in tests and continual assessment she qualified for a place in the coveted Command School.
Karen graduated from the Academy on 31st May 2260 in the 91st percentile.
Upon graduation Karen was commissioned into the Star Fleet as a Lieutenant JG and was assigned as the Beta-shift Navigation Officer of the Constitution-class heavy cruiser U.S.S. Yorktown NCC-1717. She excelled in her duties and responsibilities there for three years, after which point she was offered a promotion and a transfer.
Accepting these, in 2263 the now-Lieutenant McCafferty became the Alpha-shift Navigation Officer of the Saladin-class destroyer U.S.S. Jugurtha NCC-527. In this position she also assumed the responsibility of Division Chief Officer for the Navigation Division within the Ship Operations Department, and also the role of Assistant Chief of Ship Operations .
With the departure in 2266 of Jugurtha's Chief Helm Officer -- also the Chief of Ship Operations and Second Officer -- Captain Mark F. Daniels of the Jugurtha opted for internal promotions before bringing in replacement crew. Having performed ably and well with her current responsibilities, Karen was advanced into the Chief of Ship Operations and Second Officer roles, while remaining Chief Navigation Officer and Alpha-shift Navigator.
In another of a series of border provocations in the lead-up to the 2267 Second Klingo-Federation War , the Jugurtha was ambushed and wrecked in the L-647 star system by the Klingon D-6-class battlecruiser I.K.V. Malicious KL-706. Again, Karen acquitted herself well in the battle and it was her idea that led to the defeat of the Malicious and the survival of the remainder of the Jugurtha's crew. With the subsequent intervention of the Rihannsu War Eagle-class cruiser R.I.S. Aehallh ChR-319 -- which led indirectly to the death of Captain Daniels -- Karen was the most senior officer in the chain of command to survive and in this role she managed to keep what was left of her ship and crew safe until the Constitution-class heavy cruiser U.S.S. Vindicator NCC-1767 arrived to tow them back to Federation space.
The Jugurtha was subsequently decommissioned due to the damage she took, and her survivors were given mandatory six-months' leave from active duty. However, various factors combined to recall these people -- Karen among them -- to active duty: the looming and apparently inevitable war with the Klingons; the damaging of another Starfleet ship in another sector, leaving her without a command crew; and Karen's actions during what the media termed 'The Jugurtha Betrayal'. Starfleet Command saw fit to award Karen a promotion to Lieutenant Commander and with it her own ship, and the leeway to select several officers and crew from the Jugurtha survivors to replace crew lost to Klingon aggression.
Karen took no time in selecting trusted crewmembers to accompany her, and on 11th October 2267 Lieutenant Commander Karen McCafferty took command of the U.S.S. Kusanagi NCC-1481 and headed to the Klingo-Federation Disputed Zone.