Leo KuLeo Ku

In 2003 signed with manager 黃柏高 and joined 金牌唱片, returning to the Hong Kong music scene, and with "必殺技" took Ultimate Song Chart My Favourite Song — this award was taken twice more, in 2004 with "愛與誠" and in 2006 with "愛得太遲". In 2004, with "愛與誠", took multiple awards at that year's four Hong Kong electronic-media music awards ceremonies.

In February 2005 issued the new-songs-plus-hits record "勁歌金曲"; in March held seven Hong Kong Part I shows of the "勁歌金曲" world tour at the Coliseum, and in April added four Part II shows, eleven in all. It was at this concert that Leo Ku invited then composer Justin Lo to perform. In the same year selected as a 2005 Hong Kong Ten Outstanding Young Persons, and established the "古巨基兒童醫療基金" to help children in medical need. From 2005 to 2007 received My Favourite Male Singer at "SINA Music樂壇民意指數頒獎禮" for three consecutive years.

In 2006 released the album "Human我生", and with "愛得太遲" received awards at several awards ceremonies that year. In the same year took the media award of the Four Stations Joint Music Awards; Leo Ku received the Four Stations Joint Music Awards song award for 2006.

In 2008, at that year's Jade Solid Gold Awards, first received Most Popular Male Singer, fourteen years after debut, and thereafter held it for four editions together with 2009 to 2011; in the same year also released the two albums "勁歌金曲2情歌王" and "我還是你的情歌王". In May 2009 signed with Emperor Entertainment, and on May 30 took part in the signing ceremony in Beijing. In the same year held "Eye Fever紅館演唱會09", tickets selling out on the day they went on sale; Wikipedia calls Leo Ku the first Hong Kong singer to hold a concert with 3D visual stereoscopic effects.

At the Ultimate Song Chart Awards Presentation, Wikipedia records Leo Ku as the only singer in history to have received that ceremony's six awards — Newcomer Gold, Supreme Song, My Favourite Song, Supreme Record, My Favourite Male Singer and Male Singer Gold; also received the MTV Asia Awards Hong Kong Most Popular Singer from MTV's global channel, the first Hong Kong male singer to receive that award, and received regional awards including Best Asian Singer at the 8th Asia Song Festival; the same article separately calls Leo Ku the first Hong Kong singer invited to attend the United States "Billboard Music Awards".

On March 30, 2010 in Shanghai served as a performing guest at "世博會倒計時30天國際音樂盛典" and sang "情歌王"; on October 31 of the same year attended the Shanghai Expo closing-ceremony evening as the closing guest; on November 2 served as a performing guest at the Guangzhou Asian Games countdown-ten-days theme concert. In 2014 released the Mandarin song "愛情也有生命" sung with Joey Yung. In 2015 took part in Hunan TV's "我是歌手3" and served as a host; in the same year received the 14th World Outstanding Chinese Award, and an honorary doctorate from 紐賓士域藍仕橋大學 in Canada. In 2017 released the album "Salute to Dear Leslie", covering Leslie Cheung's songs. In 2018 returned to TVB, successively joining "流行經典50年", "東張西望" and "勁歌金曲" as a guest host, and as a senior sharing at the artiste training class.

Outside music, Leo Ku created the comic character "Kubi" and published two volumes of "The Story of KUBI"; Wikipedia records Leo Ku as the first local artiste to issue a personal comic picture book. Afterwards, together with that comic character, was invited by Madame Tussauds Hong Kong to have wax figures made; the same article calls it the first wax-figure combination in history formed by a celebrity and a self-created comic character. In 2009 established the design company A Big Company, owning the in-house fashion brands SOLO CELEB. and HTDG; as a designer also collaborated with PCCW, Motorola, MTR Corporation, the Hong Kong Jockey Club and Ocean Park Hong Kong among other bodies.

Beneficiaries of the "古巨基兒童醫療基金" are children in Hong Kong and mainland China with medical needs. On December 8, 2010, "古巨基兒童慈善基金樂城西聯小學", built with funds from the Leo Ku children's charity fund, was completed, and at the completion ceremony the foundation donated a batch of student recreational goods worth 100,000 (currency not stated in the source). In 2013 in Guangzhou received the honour of Ten Outstanding Young Persons. On January 14, 2019, Leo Ku said the sum originally meant for a press conference to explain a concert would instead, on January 15, pay red minibus fares for passengers for part of that day's hours on the Sai Wan–Tsuen Wan and Mong Kok–Tai Po routes.