About 80 members of staff from Ysgol Rhosnesni in Wrexham spent a day before the Easter break shadowing professionals from manufacturing, construction and energy firms in a bid to boost the skills curriculum.
Head Gareth Hughes said he wanted to help bridge the gap between the classroom and the world of work and to give his teachers an inspirational experience.
"It was an ideal opportunity for staff to challenge themselves and to test their abilities and extend their range of teaching techniques," he said.
The teachers were asked to come up with ideas for lessons to promote employability skills such as communication, ICT, problem solving and teamwork with the help of the businesses they visited, regardless of subject speciality.
Mr Hughes said: "I wanted them to come back and apply to the classroom the enthusiasm, drive and skills learnt from a day spent in business and, in turn, use that to raise aspirations for our pupils."
The Inset initiative was organised by charity Business in the Community, whose members work with schools in the region to help address skills shortages in science, technology maths and engineering.
Jocelle Lovell, head of operations at Business in the Community, said: "The skills gap is critical and businesses need to be thinking about how they develop their future workforce by engaging with the education sector more effectively."
Teachers at Rhosnesni are preparing a formal evaluation of their experiences, but Mr Hughes said feedback so far had been "very positive". He plans to write a paper on the experience and develop a model that other schools can use.