The saying goes "money can't buy happiness." However, he seems to run counter to these tenets since he leads quite a pleasant life.

run 在这里是动词，意思是"进行、运作"，但在短语中有特殊含义。 counter 作为名词时指"柜台"，作为动词时意思是"反对、对抗"，作为前缀表示"相反的"。 to 是介词，表示方向或关系。 run counter to 是一个固定短语，意思是"与...相反/相违背"，表示某种行为或情况与既定的原则、信条等形成对立关系。