While still with Tower of Power, he recorded his first solo album Pray For The Lion for Warner Bros. Records in 1974. At the end of 1975, Williams left the band and returned to his solo projects. Initially signing with Motown Records in 1975, he later moved to ABC Records in 1977 (which was then purchased by MCA Records in 1979). Over the next four years, he scored ten chart hits, including "Shoo Doo FuFu Ooh", "Choosing You", "You Got Me Running", "Love Hurt Me Love Healed Me", and "Midnight Girl". Williams recorded four more albums from 1977 to 1980: Choosing You, his first gold LP; Spark Of Love (contains "Cause I Love You"); Love Current; and Let’s Do It Today.
After leaving MCA, Williams recorded for the independent record labels, Rockshire and Knobhill. In 1986, he was invited to sing vocals on "Don't Make Me Wait For Love" a track from Duotones, a multi-platinum recording by Kenny G. The song became a Top 20 Billboard Hot 100 and R&B hit the following year.
His 1978 hit song "Cause I Love You" was sampled by Havoc of Mobb Deep for the track "Nothing Like Home", and by Kanye West for the songs "Overnight Celebrity" by Twista and "I Got A Love" by Jin. The track was sampled a fourth time in 2007 by Scarface for his single "Girl You Know" featuring Trey Songz & Young Jeezy sampled "Lets Talk It Over" for his single "I Do" featuring Jay-Z and Andre 3000
Since that time, Williams has continued his solo career, touring the US, Europe and South Africa, and has recently shared stages with Aretha Franklin, The Whispers, Rick James, Boney James, Bobby Womack, Ohio Players, Al Green, Usher, K-Ci & JoJo, Alicia Keys, Anthony Hamilton and Frankie Beverly & Maze. He has also expanded his career to include acting, starring in several stage plays including "Love On Lay Away" starring Deborah Cox, Mel Jackson and Martha Wash, "What Men Don't Tell" starring Kenny Latimore, Shante Moore, and Dottie Peoples, and "When A Woman's Fed Up".