The Wikipedia entry for the 99 is here. It mentions that it was designed by Sixten Sason who was responsible for the styling of Saabs up to that point. He died in 1967 while the 99 was being readied for production.
Saab 99s eventually appeared in a four-door version, but the first ones only came with two doors, as this site mentions.
The Saab 99 was not good looking. This wasn't because it was one of those stark, by-the-book "functional" designs. Instead, while aspects of its appearance might have been rationalized in functionalist terms, it was simply quirky-looking. Rather like a number of French designs.