In 1966, LaRue was approached by Lamonte McLemore and Marilyn McCoo to join their recently formed group The 5th Dimension. LaRue nearly always sang female lead on one song per album, with McCoo taking the lead on one song as well; otherwise she sang the alto voice parts along with Marilyn McCoo's soprano, being featured prominently on Stone Soul Picnic, or shared the lead with McCoo on songs including "Blowing Away", "Puppet Man", and "Save the Country". After Marilyn McCoo's departure, LaRue was lead singer on hit songs including "Love Hangover" (1976).
As of April 2009[update], the group was touring as "Florence LaRue & The Fifth Dimension" led by LaRue with Willie Williams, Leonard Tucker, Patrice Morris, and Floyd Smith. She is married to Laurence P. Kantor. She was previously married to Errol Aubry, Marc Gordon and Bennett Curland, with one child from her marriage to former manager Gordon.