Crane spent half of his childhood in the humiliating care of his overprotective mother Yan Fan, who took extra precautions for his safety by keeping him inside their hazard-free home and putting him in a suit of armor, for she thought her son to be too frail to take care of himself. When he started sneaking out of the house, however, the younger crane joined a Kung Fu class that he was amazed by, but it was too advanced for him that he kept getting injured during each session. By the time his mother found out, the sight of what he got himself into gave her heart pains and a hatred of Kung Fu, thus making Crane promise not to practice the martial art again.
Crane eventually grew up still admiring Kung Fu, but kept his distance from it by getting himself the job as janitor at the Lee Da Kung Fu Academy. There, everyone including the strict teacher looked down upon him due to his particularly skinny build and described it as something which made him lack confidence. The class's top student Mei Ling observed the skills which Crane used to tidy up the place every night, and was impressed by his speed and accuracy. She convinced him to try out for the school, and Crane, surprised but encouraged, trained himself every night after work until the day of the tryouts arrived. However, watching the other candidates fail painfully in the obstacle coarse made him loose his nerve, and was even mocked by the teacher and students for his skinny legs when Mei Ling announced that he should try out. He was instead sadly assigned to sweep up the teeth littering the floor, but wandered right into the coarse and spotted the flag meant to earn the grabber a place in the school at the far end. Using Mei Ling's encouragement, Crane ignored the teacher's order to come out of the coarse and found a way to surpass it, capturing the flag and passing with flying colors.
Kung Fu Panda: Secrets of the Furious Five
Kung Fu Panda Holiday
in Crane on a Wire it is revealed he's allergic to silk