Presently, Poon Seong Ang is Managing Director at Uni’ang Plastic Industries (Sabah) Sdn. Bhd. and Managing Director at Jaya Uni'ang (Sabah) Sdn. Bhd.
He is also on the board of Thong Guan Industries Bhd.
In the past he occupied the position of President of Federation of Sabah Industries and President-Sabah Branch at Malaysian Plastic Manufacturer Association.