The profit, for the six months to the end of November 2011, compares with a loss of £6.1m for the same period in 2010.
The club made £63m overall in player sales, while there was an investment of £74.7m in new signings and contract extensions.
Arsenal's cash reserves were up to £115.2m (from £110.4m), with turnover also up to £113.5m (from £97.6m).
Chairman Peter Hill-Wood said: "We are proud of Arsenal's record and consistency over many seasons and have the foundations in place, at every level of the club, to ensure we remain a force in the seasons ahead."
Chief executive Ivan Gazidis said: "It's important to acknowledge that the most important thing for this football club, the most important thing for our fans, and the most important thing for the board and the people that work at the club is how we do on the pitch.
"We have a healthy cash balance of £115million for the half year."But it's important to understand that not all that money's available to invest in transfers.
"We have running costs of the club, player salaries and so on, so that amount goes down during the year."We also have to keep something in reserve in case things don't go our way.
"There is money available, we don't talk about an exact figure - and there's a very good reason why we don't put an exact figure on that - because it would impact on our negotiating position.
"We have to invest efficiently, we have to invest sensibly."
Arsenal look set to end a seventh successive season without a trophy and are in danger of missing out on qualification for next season's Champions League.
And Gazidis added: "We can't gear our entire financial model around that - that expectation - because that would place the club in jeopardy if we didn't qualify.
"So we've always got to keep something in reserve in case things don't go our way."
Reports in British newspapers last week had claimed that Arsenal manager Arsene Wenger could be given as much as £100million to spend this summer, although a more realistic figure is seen to be somewhere below the £50m mark.
Several top players have been linked with moves to north London, although a priority is ensuring captain Robin van Persie signs a new deal and stays at the club next season...More>>