Born in Preston in 1935, he made his stage debut at age 13 on Blackpool's South Pier. After leaving school, he worked at a gentleman's oufitters in Blackpool before moving to London. Evenutally he became a scenic artist with Kenneth Kendall's touring theatre group in Crewe earning Equity Card. His ambition had always to been a professional actor, having risen through the ranks to appear in the West End, his television debut did not come until 1970 appearing in the sitcom Two in Clover.
Intially approached in 1972 to appear in a Comedy Playhouse by David Croft about a department store, the pilot co-written with Jeremy Lloyd around Lloyd's experience of working at Simpson's of Piccadilly. The character of Mr Humphries was only a minor part, with the character who he was to develop into barely recognisable at all. Seemingly only where the pilot was left to be broadcast at some point, it was the tragedy at the Munich Olympics which meant BBC 1 had to rearrange their schedules post haste, meaning the pilot for Are You Being Served was aired to fill air time but to take people's minds off what had happened. With an audience desperate for light relief, the show had grabbed attention through even what was saw as fortuitous circumstances.
Even then in the show's first full series early in 1973 which was put opposite Coronation Street, it was not until a repeat run later in the year did the series take off, the full spectre of Mr Humphries had been launched on the nation, but for seeming all the attention, that the character and the way that Inman was portraying him was not to everyone's taste. His mannerisms were seen as over the top, though in his defence Inman did state there were far more people in the country who were far more camp then the character he was playing in Are You Being Served and that himself and David Croft described Mr Humphries as a 'mummy's boy'. For all what was seen on this side of the Atlantic of Mr Humphries being too camp, that when Are You Being Served was shown in the United States, Wilberforce Humphries became a gay cultural icon. Leading to the series' popularity abroad with an Australian remake with Inman playing Mr Humphries in that show.
With being such a big star, it was little surprise when John Inman moved to ITV star in 'Odd Man Out' as the joint inheritor of a rock factory in Littlehampton, though much like Mollie Sugden's experience in 'Come Back Mrs Noah', the public want to see the actors playing the parts they are used to seeing them as. The reflective nature of this series looking back at it, it is by no means awful. Though its seems almost unsophsticated compared to the shows around back then, where the character of Mr Humphries worked in the surroundings of Grace Brothers, by doing the same type of character in another show. It had felt that all the ground and jokes had been covered.
Though not a ratings success, Take a Letter, Mr Jones was much like Are You Being Served? with much more of a gang feel to the sitcom adding to the cast with Rula Lenska and Miriam Margolyes to make sure that Inman was not out there alone. But as the series went out in Autumn 1981, it seems with Southern Television leaving the ITV network in December 1981 that the series was almost bound to itself. With it possibly being a success, that another ITV company would have to pick up the show and there was no guarantees of that at all. Though the feel of the series felt that sitcoms were moving into a new age during the 1980's, but of later series such as Me and My Girl, this show can owe a lot to them. Where as Odd Man Out was written by Vince Powell, Take a Letter, Mr Jones was written by Ronald Chesney and Ronald Wolfe. The experience of these writers had made the characters come to life in their previous shows but were seemingly incapable to do anything with Inman then just rework Mr Humphries with a new name.
With Grace and Favour reuniting most of the cast of Are You Being Served? in 1992, such with the other sitcoms apart from Are You Being Served? The reception of series was not favourable apart from the fans of the previous series, though it did manage to get to a second series. Inman became one of the nation's best known dames in Panto after Are You Being Served? and appeared in over 40 pantomimes. His appearances in Summer season and in other shows, showed a natural versatile ability for entertaining audiences with his own style, telling jokes and using his humour to entertain across the United Kingdom.He also toured Australia starring in a number of productions capitalising on his popularity in the country. Though not coming out as Gay official during his time on the stage and screen, Inman entered into a Civil Partnership with his partner of 33 years (at the time), Ron Lynch in December 2005.