He was the eldest son of duke Trịnh Kiểm and had a title Marquis Tuấn Đức (俊德侯).

[1] After the Northern dynasty heard the news about a confusion in Thanh Hoa, Emperor Mạc Mục Tông had assigned Prince Mạc Kính Điển to lead 100,000 soldiers with 700 warships to attack Southern dynasty.

Mạc forces came on waterfronts Linh Tràng, Chi Long, Hội Triều and occupied Bút Cương village easily and quickly.

Immediately the Mạc forces cancelled marching orders, Trịnh Cối directed his mother, wives, children and inferiors about 1,000 persons to follow marshal Mạc Kính Điển in the backing Đông Kinh.

Emperor Mạc Mục Tông had conferred him a title Marquis Trung Lương (中良侯) and his inferiors "duke".