Rommel's career success was purely as a result his military capabilities and not for being a 'Party-man' (unlike many of his contemporaries). There is little doubt that Rommel was vain and took advantage of the opportunities provided him by the War. As to whether this was politically motivated, I would say not.
In Rommel's case, his relationship with the Nazi Party perhaps began in 1937 when he was appointed liaison officer to the Hitler Youth. Through this position he came into close contact with many important Nazis. Rommel caught the attention of Hitler, who did much to support Rommel’s career. Hitler’s choice of Rommel as commander of Hitler’s bodyguard in 1939 and quick rise in rank demonstrated Hitler’s confidence in him. Rommel too liked Hitler and appreciated the preferential treatment he (Rommel) received, noting that “[Hitler] is extraordinarily friendly to me.