Stephen Gallacher was born on November 1st, 1974 in Dechmont, Scotland. He is the nephew of former Ryder Cup captain Bernard Gallacher. He played in the 1995 Walker Cup before turning pro later that year. He first played on the European Tour in 1996 but struggled to make an impact.

It was not until 2000 that Gallacher started to play his best golf. He finished in the top 100 on the money list for the first time in his career ending the year 56th. He won his only tournament in 2004 at the Dunhill Links Championship. This helped him finish 15th on the order of merit, his highest ever finish.