Prior to her casting as Hilda, Jean appeared in episodes of ITV Television Playhouse, Deadline Midnight and Z Cars, following an earlier career as a library assistant and then wardrobe mistress and stage mistress in repertory theatres in Macclesfield, Oldham, Stockport and York followed by seven years with Southport rep. Her Christmas Day 1987 departure from the Street attracted 26 million viewers, a record for the show that stands to this day. When her departure was announced, fans of the programme bombarded Granada Television with mail opposing her decision to quit, in fact the actress admits that there are still a large pile of letters unopened that she received during her final months in the show. Jean delighted her fans in 1998 though, by taking part in a spin-off, The Women of Coronation Street which was produced for VHS release only. She appeared as Hilda at her Derbyshire residence alongside another stalwart Betty Williams (Betty Driver). Jean also recorded link-material for Granada Plus's series of repeats, dressed again in costume as Hilda saying the words, " Now, there's a woman who was never scared of speaking her mind!", while clips of Weatherfield's strong women were previewed.
Back in 1988, Jean was nominated for a BAFTA for her portrayal of Hilda. Although she didn't win, she was the first soap actress to receive a BAFTA nomination, and indeed the last for twenty-one years, when EastEnders actress June Brown was nominated for a special monologue episode at the 2009 awards. Like Jean Alexander before her, June Brown did not win.
Post-Coronation Street, Jean has appeared in Boon, Where the Heart Is and Heartbeat, but her longest-running role after Hilda is junk shop owner Auntie Wainwright in long-running BBC sitcom Last of the Summer Wine, in which she guested in 1988 and 1989, before being made a permanent cast member in 1991. She appeared in the programme until its axing in 2010. She announced her retirement in 2012, two years after her last television appearance.
Jean published an autobiography in 1989. In it, she describes her childhood, her attempts to get in the acting world and, of course, her friends on the Street and the reasons why she left.
Jean, who has never married, was voted by readers of television listings magazine TV Times as the "Greatest Soap Opera Star of All Time" in 2005. In 2014 she was hospitalised for a short period with the Daily Mirror at one point mistakenly reporting that she had died.