A pair released in 2009 have now raised one male chick in a Forestry Commission Scotland wood in Fife.
Its arrival is part of a project which released a total of 85 eagles to Scotland's east coast between 2007 and 2013. The sea eagle is Britain's largest bird of prey, and the world's fourth largest eagle, with a wingspan stretching eight feet. But it became extinct in Britain around 1917.
Ron Macdonald, Scottish Natural Heritage's (SNH) Head of Policy & Advice, said: "After almost 200 years, it's wonderful to have a sea eagle chick fledge again in the east of Scotland.
"With the west coast eagles already established, this is a good step towards a healthy population of sea eagles across the country."
The East Scotland Sea Eagle project is the third phase of the Scottish sea eagle reintroduction, which began on Rum in 1975.
Up until 1985 a total of 82 eaglets were imported, under special licence, from nests in northern Norway where the sea eagle population was still expanding. The first wild bred chick since UK extinction was born on Mull in June 1985. The second phase saw a further 58 birds released in Wester Ross between 1993 and 1998.
Stuart Housden, director of RSPB Scotland, said the chick marked a huge milestone in the charity's partnership with the likes of SNH, the Forestry Commission, the Heritage Lottery Fund and the Leader Programme "to restore white-tailed eagles to their former range".
An independent study, commissioned by RSPB Scotland in 2011, found that tourists travelling to see white-tailed eagles on Mull contributed around £5 million per year to the local economy.
However not everyone has welcomed the return of the giant birds. Farmers and crofters on the west coast insist sea eagles are taking their lambs.
However, a study for SNH in Wester Ross in 2010 concluded that the birds had a minimal impact on the survival of lambs in remote parts of the Highlands.