Morrow, of Irish descent, was born in 1949 but is not a native of Charming, California. He is one of nine members who formed the Sons of Anarchy Motorcycle Club in 1967, of which he was the youngest and one of only three who were not war veterans. He did later go on to serve in the military, however, joining the US Army as an Airborne qualified Infantryman in 1969 and was deployed to Vietnam until 1972 (commemorated by a tattoo on his left arm and the paratrooper pin on his vest). When he returned from service, he remained a member of the club and opened the Teller-Morrow Automotive Repair shop with John Teller, the club President and his best friend. Whilst serving as the Vice President during the early 1990s, he was responsible for a number of murders during the SAMCRO-Mayan War, including that of Lowell Harland, Sr., a mechanic at the auto shop who became an ATF informant.
In 1993, he became the President of the club's Mother Chapter, based in Charming (which also means that he was National President), after the death of John Teller. He later went on to marry Gemma Teller Morrow, who was John Teller's wife, in the mid-1990s and make their son Jax Teller, Vice-President. It is implied that under Morrow, SAMCRO has become more of a criminal enterprise than before, much to Jax's disillusionment.[2]
On his colors, he wears patches reading "First 9" (as he was one of the original nine members), "Unholy Ones", and "Men of Mayhem". He suffers from osteoarthritis (degenerative arthritis) in his hands, which is slowly worsening as the series progresses. He makes several attempts to hide it from his brothers to protect his position as President, as a rule among members of the Sons of Anarchy prevents members from leading if they can't hold the grip of their motorcycle and ride effectively.