Cheng's biological father returned to the United States before Cheng was born. He was raised by his mother, of Amis descent.
Playing career
As a member of the Chinese Taipei youth team, teen-aged Cheng Chih-lung was two-time scoring champion in the FIBA's Under-18 Asian Championship. At the age of 19, he became the then-youngest player on the Chinese Taipei adult team and helped his team to a third-place finish in FIBA Asia Championship 1989—Taiwan's best record in the tournament since its resumption of international sports participation in the mid-1980s. From then through 1999, Cheng played for the national team in various international tournaments and helped set the team's best records in all major tournaments in the region including winning Taiwan's first gold medal in men's basketball in the 1997 East Asian Games. As the representative star player of Taiwan, Cheng was selected to All-Tournament Team for the William Jones Cup international tournament for numerous times and to the FIBA Asian All-Star roster in 1998. Initially nicknamed "Doctor" after Dr. J by his American coach, John Nealon, due to his jumping ability, Cheng Chih-lung subsequently derived another nickname, "the Loach-Dragon", from his shrewd playing style. A stable mid- and long range shooter, Cheng was also acclaimed for his smart offensive running, crafty moves, and great body coordination in the air that enabled him to "bore" through the defense like a slippery dojo loach and score from various angles and distances. As a Hung Kuo Elephant, he became the then-highest-paid basketball player in Taiwan and was the cornerstone of the "Hung Kuo dynasty" from 1996 through 1998 when the team won three consecutive championships of Taiwan's professional Chinese Basketball Alliance. He was named the most valuable player for the 1995-1996 season and for the 1998 championship series where he almost single-handedly brought his team to its third title out of a 1-3 plight in the best-of-seven series against the powerful challenger, the Kaohsiung Mars. After the Taiwanese professional league, as well as his home club, the Hung Kuo Elephants, came to disbandment due to financial difficulties in 1999, Cheng moved to play for the Shanghai Sharks of the Chinese Basketball Association in mainland China. Teamed up with the then-adolescent Yao Ming, Cheng helped the young Sharks advance to the finals for the first time in franchise history before they were defeated by the nearly invincible Bayi Rockets. First Taiwanese player to join the top-tier Chinese league, Cheng was selected to play in the postseason all-star game and received the league's sporting ethics award. After one rather successful season in China, Cheng returned to Taiwan to play for Dacin Tigers in the amateur Division-A conference where he ended his playing career in the following year.
After retirement as a player
Under the arrangement of his sponsor Wang Jen-ta, the then-president of the executive board of the Republic of China Basketball Association and a political ally of James Soong, Cheng Chih-lung ran for and won the 2001 legislative election as the People First Party nominee in the first district of Taipei County. His political career, however, was overshadowed by the scandal of extramarital affair with legislative colleague Kao Chin Su-mei, and public censures for inaction. In the capacity of legislator, nevertheless, Cheng Chih-lung was given the credit of working with the government's Sports Affairs Council to give birth to the Super Basketball League, which started to function in 2003. In the fifth season of the league's existence, Cheng Chih-lung accepted the commission to coach Taiwan Mobile Clouded Leopards and brought the losing team to an improved 15-15 record in the 2009-2010 season.
