For each of the Up Helly Aa festivals the Guizer Jarl is the leader of the Jarl's Squad (Squad Number 1), and forms the focal point.
In 1881, a Worthy Chief Guizer was chosen to lead the Lerwick procession. In 1906 the leader appeared in Viking costume for the first time and was renamed Guizer Jarl (Earl). The first Lerwick Jarl's Squad dressed in Viking suits appeared in 1921.
Each year new Jarls are elected by the various festival organising committees (usually by popular vote at a Mass Meeting), and typically serve on the committee for several years before becoming Jarl. For the Lerwick Up Helly Aa at least one person is voted onto the committee each year to become Guizer Jarl 15 years after their election. At the Delting Up Helly Aa the wait is currently 13 years, but typically in the other festivals the wait is much shorter, usually 5 years or less. In Lerwick it is rare for a prospective Jarl to serve the full period due to the resignation or death of preceding committee members.
A person elected as Guizer Jarl only holds that position once, although there have been a few exceptions. E. S. Reid Tait was the Guizer Jarl for the Lerwick Up Helly Aa 1911 but fulfilled the role again in the Lerwick Up Helly Aa 1912, substituting for an absent H. Kay due to a bereavement in the family. In the Lerwick Up Helly Aa 1989 Charlie Simpson (the 1988 Jarl), stood in for Willie Black during the day's activities as he was suffering from a bout of flu. By the evening however, Willie had recovered enough to attend the procession and burning and managed to make it round all the evening halls. Tony Herculson was the first Guizer Jarl for the Nesting and Girlsta Up Helly Aa in 1961 and became Guizer Jarl again for the 50th anniversay of the festival in the Nesting and Girlsta Up Helly Aa 2011.
The Guizer Jarl is usually dressed differently from the rest of his Squad so he is instantly recognisable. In Lerwick the Jarl's suit is superficially similar each year, with the same shield, axe, breastplate and helmet used, although there are variations to allow for different sized Jarls!.
Guizer Jarls from ten of the 2011 Up Helly Aa festivals.