
Chow, who was sworn in at 11.10am, was accompanied by his wife Tan Lean Kee.
He succeeds DAP secretary-general Lim Guan Eng, who was appointed as finance minister on Saturday.
Chow, a former journalist, began his political career with a three-term stint as Tanjong MP, from 1999 to 2008. He was previously political secretary to DAP stalwart Lim Kit Siang.

The 60-year-old has also held the Padang Kota state seat for two terms since 2008, following two unsuccessful attempts in the 1999 and 2004 general elections.
In last week’s polls, he retained Padang Kota and won the Tanjong parliamentary seat again after a one-term gap in 2013.