甄玄成熟讀經史，擅長撰寫文章，年少就獲梁簡文帝知曉，任命為錄事參軍跟隨蕭詧鎮守襄陽，轉任中記室參軍，參與咗唔少政事決策。後來甄玄成認為江陵兵器充足，於是懷有異心，祕密寫信畀梁元帝投誠，但信件落入蕭詧手中。蕭詧信奉佛教，常願不殺誦讀《法華經》嘅人，甄玄成因為經常誦讀《法華經》而免死。之後蕭詧見到佢經常講：「你真係得到《法華經》嘅力量啊。」西梁建立後，佢先後任職中書侍郎、御史中丞、祠部尚書和吏部尚書，大定六年（560年）死，贈侍中、護軍將軍，有文集《甄玄成集》十卷，賦一篇《車賦》。
Zhen Xuan is mature in reading scriptures and history, good at writing articles, and was known by Emperor Jianwen of Liang when he was young, and was appointed to join the army as a record to follow Xiao Chazhen to guard Xiangyang, and was transferred to the Central Records Office to join the army, and participated in many political decisions. Later, Zhen Xuancheng thought that Jiangling had sufficient weapons, so he had a different heart and secretly wrote a letter to Emperor Liang Yuan to surrender, but the letter fell into the hands of Xiao Cha. Xiao Cha believed in Buddhism and often wished not to kill people who recited the Lotus Sutra, and Zhen Xuancheng was spared death because he often recited the Lotus Sutra. Later, Xiao Cha saw that he often said, "You really have the power of the Lotus Sutra. After the establishment of the Western Liang, he successively served as the Zhongshu Shilang, the Imperial History Zhongcheng, the Ancestral Department of Shangshu and the Ministry of Officials, died in the sixth year of Dading (560), and gave the general of the service and the army, and there were ten volumes of the anthology "Zhen Xuancheng Collection", and a "Che Fu".