It was first published as the Belfast Evening Telegraph on 1 September 1870 by brothers William and George Baird. Its first edition cost half a penny and ran to four pages covering the Franco-Prussian war and local news.
The evening edition of the newspaper was originally called the "Sixth Late", and "Sixth Late Tele" was a familiar cry made by vendors in Belfast City Centre in the past.
The Belfast Telegraph was entirely broadsheet until 19 February 2005, when the Saturday morning edition was introduced and all Saturday editions were converted to compact. The weekday morning Compact Edition, launched on 22 March 2005, struggled to replicate the evening newspaper's success. Its editorial content has been much more tabloid, with a greater entertainment story count than the evening paper. Much prominence is given to English-based sport, and some general features and columns are shared with The Independent and Irish Independent.
The paper now publishes two editions daily, Belfast Telegraph final edition and the North West Telegraph which is distributed in Derry.
By the end of the 20th century, the Belfast Telegraph was selling more than 100,000 copies daily.
According to the UK Audit Bureau of Circulations, the paper still had an average daily circulation of 94,540 between June 2004 and January 2005. But since then sales have fallen steadily year on year, the average sales figure for the first six months of 2009 showing a large drop of 10.5% year on year to 68,024, then to just over 66,000. There was a slight upturn in the first six months of 2010.
But such was the overall decline in circulation that in the ABC figures for January to June 2012, the Irish News surpassed the Belfast Telegraph in terms of full-priced copies sold, with the once unrivalled Telegraph now trailing the Irish News by 1,284 copies per day. They show that the regional daily saw its circulation fall by 9.2 percent year on year to an average of 53,847 for the first six months of the year. However, when its discounted and give-away prices are taken into account, the Belfast Telegraph still has the highest circulation as audited by ABC of the local daily newspapers including the NI edition of the Daily Mirror 52,009, Irish News 42,084 and News Letter 22,198.
The Belfast Telegraph is read by 174,000 people daily according to NITIG 2012, annual readership research subscribed to by media owners and advertising agencies throughout Britain or Ireland. Its readership shows the best balanced readership across all communities in Northern Ireland.
In the period of January to June 2013 it dropped by 8.6% to 49,228, but remained the best selling newspaper in Northern Ireland.
The Belfast Telegraph is the primary title of Independent News & Media (NI) Ltd. It carries many supplements including:
- nijobfinder - appears in the paper every Tuesday and Friday. The nijobfinder brand launched its website in December 2008, , which quickly rose to prominence to provide be the number one Job Site  in Northern Ireland. An ad in nijobfinder is read by 466,000 people making it the no 1 resource for finding employment in Northern Ireland, by some distance.
- nicarfinder - is the Wednesday supplement; every ad published with nicarfinder is seen by 130,000 people. nicarfinder launched a new version of their website, , in May 2012; it has one of the most powerful search engines offering users unique functionality in car search.
- HomeFinder - the property supplement, focusing on the home - from interior decor, to house prices, to the latest and most glamorous homes on the market in Northern Ireland. is the topmost property website in Northern Ireland, showing thousands of houses currently on the market and content from the Home Finder.
- Weekend Supplement
- OutThere Guide - the guide is printed monthly and is a resource for those socialising around Northern Ireland.
They ceased to print the Ireland's Saturday Night sports evening newspaper in July 2008.
A sister paper is Sunday Life. Also associated is Ads for Free. And the paper holds the printing contract for The Daily Mirror, The Sun, The Independent, The Daily Telegraph, The Irish Daily Star, The Daily Star and The Times for Northern Ireland.
The Belfast Telegraph was named as Best UK Regional Newspaper of the Year 2012 by the Society of Editors Regional Press Awards.
At the Coca-Cola CIPR Awards, the Belfast Telegraph scooped the following awards: Newspaper of the Year, Website of the Year, Supplement of the Year for its Titanic Tales series, Business Journalist of the Year Claire McNeilly, Production Journalist of the year for Heather Byrne, Features Journalist of the Year for Jane Hardy and Lifetime Achievement Award for former Editor Roy Lilley.