The answer is already present in the title of the question: recursion. Use it. 
sub walk {
    my ($person, $level) = @_;
    say " " x $level, $person;
    for my $lower (@{ $hash{$person} }) {
        walk($lower, $level+1)
    }
}

walk("CEO",0);

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In reply to Re: Recursive walk through hash of arrays by choroba
in thread Recursive walk through hash of arrays by paulzakas

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