Title: Ecchuu no Kami
Also known as: Tsutsui Fujikatsu (筒井藤勝), Tsutsui Fujimasa (筒井藤政), 後順慶

Son of the Sengoku general Tsutsui Junshou in Yamato, Junkei succeeded his father as clan head in 1550 when he was only 2 years old upon his father's death of illness. His uncle Tsutsui Junsei acted as his guardian. However, Tsutsui Junsei died in the invasion of Yamato by Matsunaga Hisahide in 1564, and Junkei lost Tsutsui Castle, the clan's main castle, to Hisahide.

In 1566 he joined with the Miyoshi Triumvirate in order to recover Tsutsui Castle, but Hisahide proved too much to handle. Junkei then became a vassal of Oda Nobunaga, and fought several battles under him, including the seige of Mount Shigi in 1577 where Hisahide was defeated. After the battle Nobunaga rewarded Junkei with the province of Yamato.

After Nobunaga's death, Junkei became a vassal of Toyotomi Hideyoshi. He died at 36 of illness. His tomb is located near the remains of Tsutsui Castle in what is now Tsutsui Junkei History Park.