He was born in Shanghai in 11/19/1935. He came to HK in 1949 and started working as an assistant cinematographer at Nanguo Studio. He eventually joined Shaw Brothers in 1964 where he worked with Chang Cheh as assistant director in The Butterfly Chalice (1965) and Tiger Boy (1966). He directed the first ever colour Wuxia for the studio Temple of the Red Lotus (1965) and its subsequent sequels Twin Swords (1965) and The Sword and the Lute (1967). His last film for the studio will be Swordsman at Large (1971).

Hsu joined Golden Harvest (HK) Limited in 1971 and directed the Chinese version of Zatoichi and the One-Armed Swordsman, a parallel to the Japanese version directed by Kimiyoshi Yasuda. (Excerpt taken from Hong Kong Film Archive).

1935年生于上海，1949年从上海来港定居，刚开始在南国片场当摄影师罗君雄的摄影助手，两年后签约新华电影公司担任摄影师，第一部挂名影片为姜南导演的《采西瓜的姑娘》。

1964年，徐增宏加盟邵氏担任摄影师、编剧及副导演，编剧过李翰祥导演的《一毛钱》，在何梦华导演的《血溅牡丹红》及张彻导演的《虎侠歼仇》担任副导演。1965年，和邵氏转签导演合约，升任导演，首作为《江湖奇侠》，是邵氏开创新派武侠片的主力人物之一。其后又执导了《琴剑恩仇》、《神剑震江湖》、《七侠五义》、《玉面飞狐》、《萧十一郎》等多部电影。

1971年，徐增宏离开邵氏，转投嘉禾，为嘉禾公司与日本演员胜新太郎合资制作的电影《独臂刀大战盲侠》担任中文版导演（日文版由安田公义担任）。同年，嘉禾支持他到台湾创立苦干影片公司，创业了《一夫当关》、《侠义双雄》、《一娇二俏三更妙》等影片。

1980年，徐增宏返回香港在天工冲印公司担任经理，现居台湾。