The positive figure was achieved despite revenues falling for the 26 weeks to 3 July 2010.
During the period, the company achieved a turnover of £207.3m, a 5.2% like-for-like drop on 2009.
John Fry, chief executive officer of Johnston Press, said: "In the first half, the group achieved an operating profit before non-recurring items of £40.5m, up from £38.2m in the prior year. This represents our first operating profit increase reported since 2006."
It reported a pre-tax profit of £44m, which compared to a loss of £93.6m for the same period last year, brought about by massive restructuring in order to cope with its large debt.
Johnston's cost-cutting measures also impacted on the first-half results, with total costs for the period £13.6m lower than last year.
Net debt was reduced by £20.9m since the start of the year, however, at £401.1m it is still drawing "significantly higher interest costs", the company said in a statement.
Advertising revenue had continued to decline, but the rate of reduction was getting smaller; down to 6.3% in the period from 32.7% in the first half of 2009.
Fry added: "As we move into the second half of the year, we have seen the improving trend in advertising revenues continue with total advertising in the first six weeks on a like-for-like basis only down 3.7%.
"These industry-leading trends that demonstrate the strength of our publishing portfolio along with our continued focus on costs, efficiencies and debt reduction, give the board confidence that, in the absence of a further deterioration in the UK economy, the outcome for the group in 2010 will be in line with current market expectations."