You may be able to use a Regular Expression for this, such as:

my ($last_name, $first_name, $middle_initial) = ( $_ =~ /(\w+)\W*?(\w+
+)\s?(\w)?/) ;
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Here's the subroutine using the regexp you can plug right into liverpole's solution.

sub parse_name {
    my ($last, $first, $mi) = ( $_[0] =~ /(\w+)\W*?(\w+)\s?(\w)?/) ;
    return [$first, $last, $mi];
}
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Updated: Noticed I missed the first no middle-initial case, oops!