The title “Gacchādhipati” means head (ācārya) of a particular gaccha/sect within the Jain Śramaṇa saṅgh.

There is no single, universal “first Gacchādhipati” for all of Jainism. Each gaccha (like Tapāgaccha, Añcala/Ācala Gaccha, Pāṭhaśāhā Gaccha, etc.) has its own line of ācāryas, and therefore its own “first” Gacchādhipati.

So, the answer depends on which gaccha you are asking about. For example:

• The founder-ācārya of a gaccha is usually regarded as its first Gacchādhipati.
• Different Śvetāmbara and Digambara traditions have different gacchas and lineages, so their “first Gacchādhipati” will not be the same person.

Because you have not specified the name of the gaccha, I cannot truthfully give one specific name as “the first Gacchādhipati.”