Tina O'Brien was born 7th August, 1983 in Rusholme. She took over the role of Sarah Louise Grimshaw (born Tilsley, maiden name Platt) from Episode 4708 (31st October 1999). She was the third person to play the role of Sarah, taking over from Lynsay King, who had last been seen earlier the same month. Other parts have been in the Coronation Street: Pantomime, ITV's Dick Whittington pantomime, and her TV debut in Children's Ward. She also appeared in Clocking Off, where her characters' brother was played by her future Street half-brother David's actor, Jack P. Shepherd.

Tina won Best Newcomer at the 2000 National Television Awards. She is godmother to Amy and Emily Walton, who played her daughter Bethany. Tina has a daughter with former co-star and screen husband Ryan Thomas, who plays Jason Grimshaw. They had been dating since 2004, although they have now separated. She previously dated Bruno Langley who played Todd Grimshaw, brother of Jason who her Coronation Street character also dated!

Since leaving the Street she has appeared in an episode of Blue Murder and also, in June 2010, in a TV film "The Secret Diaries of Anne Lister".