In fact, Barnsley have won their last two games with caretaker manager duo Mark Burton and Paul Heckingbottom in charge.
Johnson has guided Oldham to ninth in League One and will be joining his new club who are in 16th spot.
The Oakwell side have been looking for a new manager since they Danny Wilson was sacked on February 12.
Johnson became the youngest manager in English football when he picked up the reins at Boundary Park in March 2013 at the age of 31.
He helped them avoid relegation from League One in his first season and guided them to a 15th-place finish in the last campaign.
During his spell at Oldham his team won 36 times, suffering 35 defeats with 32 draws.
It is expected Johnson's first game in charge will be Saturday's visit to Gillingham.
There has been no comment yet from Oldham on a possible replacement or whether Johnson is taking his back-room team with him. Latics face have a tough lancashire derby versus Preston on Saturday.