Staff, governors, pupils and parents at Garstang High School, along with community sports groups, have been campaigning for the new state-of-the-art sports centre at the school for the past six months, although the need was first recognised 10 years ago.
The centre is expected to occupy an area of 1,183 square metres, with space for four badminton-sized courts, a fitness area, a reception, a social area and changing rooms.
It will open from 9am-9pm on Mondays to Saturdays, and 9am-5pm on Sundays and public holidays.
The promise of funding is the latest celebration for the Bowgreave school, which has seen a change of image and a major improvement in exam results.
Headteacher Phil Birch described the funding as "brilliant news", although he added that details and a timescale for the project are not yet known.
The school launched the sports hall campaign at its 50th anniversary celebrations in October last year.
In an effort to persuade Lancashire County Council to provide funding, they asked members of the public to 'buy a brick' and raise £40,000 to prove how badly the facilities were needed. By April, they had raised £15,000.