Wang Leehom (born May 17, 1976), sometimes credited as Leehom Wang, is a Taiwanese-American singer-songwriter, record producer, actor and film director. Formally trained at the Eastman School of Music, Williams College and Berklee College of Music, his musical style is known for fusing Chinese elements (such as Beijing opera, traditional styles of ethnic minorities, Chinese classical orchestra) with hip-hop and R&B. Wang debuted in 1995 and since then has released over 25 albums, with sales of over 50 million copies. He is also a four-time winner and 19-time nominee of Taiwan's Golden Melody Awards, the "Grammys" of Chinese music.

Wang's contract with Decca Records was terminated after the release of his fourth album White Paper in the summer of 1997. After graduating with honors at Williams College, he released his first award-winning album Revolution under Sony Music Entertainment in August 1998. The album became his breakthrough album, immediately selling over 10,000 domestic units in the first week of release. Critics rated the album highly, and it won Wang two Golden Melody Awards--Best Producer and Best Mandarin Male Singer. He was the youngest artist to win in either of the two categories. Wang has been nominated the Best Mandarin Male Singer at the awards every year since the success of Revolution. The singles of Revolution also achieved similar success-"Revolution" became Wang Leehom's first No. 1 single, becoming one of the top 20 songs of the year on Channel V Taiwan.  He continued his studies by attending Berklee College of Music's Professional Music program, with voice as his principal instrument. In 1999, Wang released his sixth album Impossible to Miss You, which combined the catchy pop melodies of Revolution with a quirky style of new-found dance-pop. It became his then best-selling album, selling over 1 million copies. All of the album's promotional singles topped KTV charts and yearly music charts, including the upbeat "Julia" and the ballad "Crying Palm". His album also attracted international attention-Wang won three Best Male Vocalist awards at three different award ceremonies and was also awarded for his musical merit in the album at the 1st annual Asia Chinese Music Awards.  At the beginning of the millennium, Wang began filming for several Cantonese-language Hong Kong blockbusters, which inspired him to study the Cantonese language. He included a Cantonese track, "Love My Song," in the Hong Kong release of Forever's First Day (2000), his seventh album. Unlike his previous two albums, Forever's First Day consisted mainly of melodic R&B tunes. The album's eponymous single is a tragic romantic ballad, speaking of a separation of two individuals. Although raised in New York for most of his life, living in Taiwan made Wang realize the deep roots of his Chinese heritage. Forever's First Day yielded a cover of his uncle's signature song "Descendants of the Dragon"; Wang re-arranged the song with heavier rock and dance elements. The song also included a rap bridge that summarized experiences of his parents living as a Chinese American in New York.

Using a quote from the above article, answer the following question: what is Wang Leehom best known for?
It became his then best-selling album, selling over 1 million copies.