Sun Yang?had been labeled China's "bad boy" of swimming for a number of out-of-pool scandals, but the young star says he has learned a lot from the ups and downs and is ready to embark on a new phase of his career.

Sun, who shot to fame after winning gold?medals in the 400m and 1,500m freestyle events at the 2012 London Olympics, has been involved in a series of scandals over the past year or so.

In early 2013, he was suspended from engaging?in commercial activities after quarreling with longtime coach Zhu Zhigen, who disapproved of his romance with an air stewardess and criticized his breaking of teamrules.

In November,Sun was ordered to spend a week in detention for driving without a license after being involved in a car accident in Hangzhou, Zhejiang province.

China's swimming authorities slapped a blanket suspension on him, banning him from all training and competitions before allowing him to make his return at this year's Chinese National Championships, which doubled as trials for the Asian Games.

Sun repaid the faith shown in him by winning his signature event, the 400m freestyle, over archrival Park Taehwan of South Korea and Japanese 200m champion Kosuke Hagino at the Incheon Asian Games on Tuesday.

"I've beenworking really hard to come back fromthe lowest point inmy career over the past half year," said the 22 year old Zhejiang native.

"A lot of things happened in the last 12 months and I think I've learnedmy lessons and regrouped," Sun's new coach, Zhang Yadong, the former mentor of female Olympic champion Luo Xuejuan, has witnessed first hand the swimmer's recovery from the setbacks.

"Every young athlete has to grow from setbacks, especially someone with a strong personality like Sun," Zhang told China Daily after the 400m final.

"Though his skills and conditioning are yet to recover 100 percent, I think he'smatured. There is no perfect athlete on or off the court. I hope the public can forgive his faults and encourage him to be better."

The governing body's ban on Sun's commercial activities seems to have been lifted as a commercial for a renowned Chinese insurance company was released online during the Asian Games.

More than 2.1 million fans have viewed the commercial since its premiere on Sina?Weibo, China's popular social media plat form earlier this month, whch suggests Sun's market appeal remains high.

Wang Lusheng, director of the national swimming administrative center, urged the media and public to get behind Sun.

"Sun has shown evidence that he has really grown up. We will also do our job to better educate and manage our athletes, not only train them to be excellent in sports but also guide them to be all around talents," said Wang.