The position of Clan Leader in the Immortal Spirit Realm was actually similar to that of the High Priest. There were certain requirements for serving as Clan Leader as well. First of all, the position likewise had to be filled by an ascended cultivator from the lower realm.
However, that person need not necessarily have been a clan leader in the lower realm. Yet among the current clan, his cultivation would have to rank roughly third, meaning his strength was second only to the High Priest and the Great Elder.
Only then would the clan members be convinced to let him handle the clan's affairs. A lower-realm Clan Leader like Gong Shanhe, despite having rendered great merit after ascending, simply did not meet the cultivation requirement.
Thus, he could only settle down and cultivate first. Once he broke through from the Nascent Soul or Spirit Transformation Realm into the Void Refinement Realm, he would first enter the lowest elder rank of the Void Refinement Realm.
As for whether he could later become Clan Leader, that would depend on whether, as his strength increased, he could eventually fulfill all the other requirements as well.
While speaking of this, Gong Shanhe also mentioned the Tianli Clan Great Elder whom Li Yan had met when he went to the Wind God Continent. That man had already ascended to the Immortal Spirit Realm as well.
It was just that his current cultivation had only recently broken through into the Spirit Transformation Realm. As for breaking through into the Void Refinement Realm later, he might not be able to accomplish it even in this lifetime!
The reason was that the Great Elder had encountered immense peril during his ascension. The fact that he had not died on the way up was already his greatest fortune.