Let
A
be a unital algebra with idempotent
e
over a 2-torsionfree unital commutative ring
ℛ
and
S
:
A
⟶
A
be an arbitrary generalized Jordan n-derivation associated with a Jordan n-derivation
J
. We show that, under mild conditions, every generalized Jordan n-derivation
S
:
A
⟶
A
is of the form
S
x
=
λ
x
+
J
x
in the current work. As an application, we give a description of generalized Jordan derivations for the condition
n
=
2
on classical examples of unital algebras with idempotents: triangular algebras, matrix algebras, nest algebras, and algebras of all bounded linear operators, which generalize some known results.