The following is a translation from Kol HaTor, chapter 1.
Od Yosef Chai (Yosef Still Lives) - Also many from the Forefathers, and many from the Prophets of Hashem, Kings of Israel, and many of the Tanna'im and Amora'im, and many of the Gedolei Yisrael and Men of Action in all the generations were in the line of Moshiach ben Yosef.
The first was Avraham Avinu in the secret of "How will I know that I will inherit it", and as is known, any language regarding inheritance which is said about Eretz Yisrael is in the line of Moshiach ben Yosef, and thus it is hinted in the word "I will inherit it (irashenah)" which is equal in gematria to "Moshiach ben Yosef". Avraham Avinu started with the first Atchalta DiGeulah, meaning redemption of the Kedushah of below, i.e. the earth of Eretz Yisrael.
Yitzchak Avinu entered into the line of Moshiach ben Yosef from the day of the Akeidah. This is also hinted at in his name Yitzchak which has the letters spelling Keitz Chai.
Yaakov Avinu, from the day he fought with the ministering angel of Esav, and Yaakov came complete. Complete to Sukkot.
Yehudah, from the day he saved Yosef.
Yosef, from the day of his first dream.
Moshe Rabbeinu from the day he took with him the bones of Yosef.
Yehoshua bin Nun, who was the first in Hashem's War with Amalek.
Shaul and David who both worked in the Wars of Hashem, and as is known that every War of Hashem is in the line of Moshiach ben Yosef, etc.
And in the later generations, also the Holy Ariza"l and his special student Rav Chaim Vital, and the Holy Rav the Ohr HaChaim were of the line of Moshiach ben Yosef as is known.
And in the last generation it is our Rabbi the GR"A who is the light of Moshiach ben Yosef, whose light goes before us and lights up the way. And also a few of his students merited, those who follow his command in the Vision of Tzion to receive from his spirit and from his great light in this line (of Moshiach ben Yosef).