Simone's bearing and stage presence earned her the title "High Priestess of Soul". She was a piano player, singer, and performer, "separately and simultaneously". On stage, Simone moved from gospel to blues, jazz, and folk, to numbers with European classical styling, and Bach-style fugal counterpoint. She incorporated monologues and dialogues with the audience into the program, and often used silence as a musical element. Simone compared it to "mass hypnosis. I use it all the time". Throughout most of her life and recording career she was accompanied by percussionist Leopoldo Fleming and guitarist and musical director Al Schackman.
Simone had a reputation in the music industry for her volatility. In 1995, she shot and wounded her neighbor's son with a pneumatic pistol after his laughter disturbed her concentration. She also fired a gun at a record company executive whom she accused of stealing royalties. According to a biographer, Simone took medication for a condition from the mid-1960s on. All this was only known to a small group of intimates, and kept out of public view for many years, until the biography Break Down and Let It All Out written by Sylvia Hampton and David Nathan revealed this in 2004 after her death