The group still felt straitjacketed by the Motown assembly line production formula and in 1969, they exited Tamla to resuscitate the T-Neck label. Their next release, the muscular and funky "It's Your Thing," hit number two on the U.S. charts in 1969 and became their most successful record. In 1973, the Isleys scored a massive hit with their rock-funk fusion cover of their own earlier single "Who's That Lady," retitled "That Lady." The album 3 + 3 also proved highly successful, as did 1975's The Heat Is On, which spawned the smash "Fight the Power." As the decade wore on, the group again altered its sound to fit into the booming disco market; while their success on pop radio ran dry, they frequently topped the R&B charts with singles like 1977's "The Pride," 1978's "Take Me to the Next Phase," 1979's "I Wanna Be with You, Pt. 1," and 1980's "Don't Say Goodnight."
In 1986, O'Kelly Isley died of a heart attack and brother Rudolph left to join the ministry soon after; Ronald forged on, however, teaming with younger siblings Ernie and Marvin for a handful of albums, including Mission to Please (1996), Eternal (2001), Body Kiss (2003), and Baby Makin' Music (2006). He also released a pair of solo works: Here I Am: Isley Meets Bacharach (2003) and Mr. I (2010). ~ Jason Ankeny, Rovi