Smith started his professional acting career in 1959, and although better known for his later roles on television, started as a stage performer with The National Theatre, roles include Merry Widow, Camelot, My Fair Lady, Fiddler on the Roof and Anthony and Elizabeth and numerous others Before appearing on Neighbours, Smith had previously acted in guest roles in drama series such as the Crawford Productions police dramas Homicide, Division 4 and Matlock Police. He had a regular role in long-running Australian television serial Bellbird, made a guest appearance as a police detective in The Box in 1975, and had a semi-regular role in serial Prisoner, in which he served as script editor of for most of its eight-year run and became Associate Producer later in its run. Smith featured in Series 11 of I'm a Celebrity... Get Me Out of Here! to set the camp-mates challenges. He did not join the camp-mates.
''Neighbours''
Smith became best known through his portrayal of Harold Bishop in the soap opera Neighbours from 1987 to 1991, and returning in 1996. He switched to recurring status from 2008 to 2009, becoming one of its longest serving characters. For his portrayal of Harold, Smith received a nomination for a Gold Logie Award in 2009. In December 2010, Ryan Moloney revealed to TV Week that Smith would be returning to Neighbours in 2011. Smith appeared for six weeks from May 2011. Smith returned to Neighbours in 2015, with former co-star Anne Charleston for the 30th anniversary. He also appeared in a documentary celebrating the anniversary titled , which aired in Australia and the UK in March 2015. In April 2018, Smith admitted that he should have left Neighbours sooner and admits he felt typecast. Smith admitted "he wasn't aware he was becoming 'Harold from Neighbours while he was on the show" and joked that when he auditioned for other roles he would be told "Oh you were in Neighbours, you were Harold, you couldn't possibly be a murdering paedophile".
Personal life
Smith was 54 when his mother Connie Smith, realising she had very little time to live, told him that he had been adopted. After her death, Smith went in search of his natural mother Peg Kline, whom he finally found. According to Kline's story, Smith was conceived when she was fourteen, the product of rape, and was put up for adoption. Kline eventually married and had two children from this marriage. She never told anyone besides her husband about her first son until she was contacted by Smith via a letter. Kline contacted Ian's wife Gail Smith, who mentioned that her husband was a prominent Neighbours actor, to which Kline replied, "I've never seen Neighbours in my life". Smith and Kline were reunited and he built a strong relationship with his mother and two half-brothers, although Smith said that he did not feel a mother–son relationship. He called Kline "one of my best friends". Peg Kline died in May 2005 after a battle with cancer. Smith told his story in an exclusive interview on the biographicaldocumentary seriesAustralian Story in March 2005. He had also described the situation in a BBC interview some years before. Smith lives in Melbourne. Although Smith was raised as a Roman Catholic, in a 2008 interview, he identified as an atheist.