Lin Gengxin enrolled in the Shanghai Theatre Academy in 2007. During his college years, Lin appeared in low-budget films, television shows, short films and advertisements. He worked with experienced actors such as Betty Sun and Alex Fong.
Scarlet Heart is a television program based on Tong Hua's novel of the same name (2006). It first aired on "Hunan TV" on 10 September 2011. Filming finished on 20 March 2011. Lin portrayed the 14th Prince Yinti, a youthful, carefree and gentle person who was willing to sacrifice his life to protect and support his eighth brother. Lin won a Sohu drama festival award for "best male newcomer". Scarlet Heart is not Lin's first TV but definitely is one to let him known by everyone and get numerous fans.