Altea was born in Leicester, England to Lilian and William Edwards, and has two brothers and three sisters. Her formal education ended at the age of 16 when she left school and then got married when she was 19. Altea is divorced and has one daughter born in 1970.

In 2001 Altea inherited a farm in Dorset, Vermont from Llewella Day, an elderly cancer victim. Ms. Day changed her will shortly before she died, thereby cutting her family out and leaving the $740,000 farm to Altea, with the desire it remain a working farm. Altea successfully fought Day's family's attempts to invalidate the will, and...against Ms. Day's wishes...demolished the farm house to make the farm into a "a healing foundation". The family argued in court that Altea used "undue influence to convince a dying woman to change her will."

Regarding the 2003 Bullshit! episode, Kevin Christopher of the Skeptical Inquirer wrote that the segment on Altea "was a nice expose of Rosemary Altea during a taped reading arranged by Showtime. Viewers got a clear picture of how she worked the small group of people present for readings prior to the taping in order to glean information for later use. They also learned how her publicist, Joni Evans, seeded the group with people whose biographies were already known to Altea in order to boost her on-camera success."

On January 26, 2007 Altea appeared on Larry King Live with skeptic James Randi. When asked on the show to take the One Million Dollar Challenge, she refused to answer whether she would take the test.

In 2009, Altea learned that Denise M. Hall, her accountant, had stolen $200,000 from her since, using four credit cards to obtain cash advances, forging cheques and giving herself unauthorized electronic paychecks all under Altea's name.