  It has been proposed that the superconformal index admits a novel
reformulation, called giant graviton expansion. In this paper, we investigate
the properties of dual $AdS_5$ black holes using the giant graviton expansion
framework. First, we compute the entropy of black holes in $AdS_5\times S^5$
with fixed charges through a large $N$ saddle point analysis on the giant
graviton index and further extremize it in the wrapping number. We identify a
specific regime of fugacities where our saddle point analysis is valid. It
turns out that this condition ensures the absence of closed-time-like curves
and the stability of dual black hole solutions with equal charges. In addition,
the giant graviton expansion of the index provides insights into how small
black holes in AdS can be interpreted as bound states of branes. We extend our
study to include the giant graviton expansion with the insertion of a half-BPS
surface defect in $\mathcal{N}=4$ SYM with a $U(N)$ gauge group. Finally, we
test the giant graviton expansion in various holographic theories whose dual
geometries are $AdS_5\times S^5/\mathbb{Z}_k$ and $AdS_5\times SE_5$.
