He hailed from Rencheng 任城 (modern Jining 濟寧, Shandong) and was a secretary (sheren 舍人) of Prince Liu Qi 劉啓, the future Emperor Jing 漢景帝 (r. 157-141 BCE). He was later made Superior grand master of the palace (taizhong dafu 太中大夫). On the accession of Emperor Jing to the throne, he was appointed Chamberlain for attendants (langzhong ling 郎中令).
Zhou Ren was known as a man of few words and good deeds and never pointed at other persons's faults. When the Emperor asked him about other officials' behaviour, Zhou always answered that the emperor might examine them himself. Emperor Jing therefore esteemed him very high, but Zhou refused all presents by the emperor. He also refused the bribes of other officials or the princes that wanted to have access to the emperor via Zhou Ren's introduction. Zhou Wen was also known for his sparingness and constanlty repaired his old clothes. Emperor Wu 漢武帝 (r. 141-87 BCE) likewise esteemed him as an intimate courtier of his father, but Zhou Ren retired soon.