He, along with his team mates, had a chance to compete with other 11 teams in mainland China for the chance to the Old Trafford. Kitchee
In March 2008, Kitchee submitted the player list for 2008 AFC Cup. Leung was selected and listed on the list.
Just a month later, on 26 April 2008, Leung Ka Hai made his senior career debut against Lanwa Redbull as a 75th-minute substitute.
At the age of 15 years and 4 days, Leung was the youngest-ever debutante in the Hong Kong First Division League, a record previously held by his teammate Lo Kwan Yee. Tai Chung
In the summer of 2011, Leung was loaned to Hong Kong Second Division club Tai Chung.
However, in January 2012, he was called back to Kitchee for the 2012 AFC Cup
Sunray Cave JC Sun Hei
Leung joined Sunray Cave JC Sun Hei on loan from Kitchee until the end of 2013–2014 season. Like a usual Brazilian full-back, Leung always joins attack from the back in a match although he plays as a right-back.
Due to his aggressive playing style, he was called as Cafu.