The Kingdom bridge a nine year gap
The Kerry and Dublin under-21s have both earned provincial honours in their respective championships.
For Kerry, their triumph was their first Eirgrid Munster Under-21 football title since 2008.
The Kindgom had been runners up in 2016 and prior to that in 2010, 2011 and 2012.
Matthew O'Sullivan and Conor Geaney got the goals in a commanding 2-16 to 0-6 win over reigning champions Cork, who had won 11 titles since the turn of the Millennium.
But Kerry have now levelled things up on the all time list of Munster under-21 champions, with both they and Cork now on 26 titles each.
Dublin co-captains Con O'Callaghan and Cillian O'Shea raise the trophy ©INPHO/Morgan Treacy
Meanwhile, Dublin have completed a record four Leinster titles in a row.
They beat Offaly 2-14 to 0-8 in Portlaoise in a comfortable result for the champions.
The first Dublin goal came from Tom Fox and Stephen Smith added another goal in extra time.
In a similar way to Cork had done in Munster, Dublin have dominated in Leinster.
Since the turn of the Millennium, they have now won 10 Leinster under-21 titles and reached two further finals.