Jonny Keeley won his seat for the Lib Dems in 2016 and was re-elected the following year.
The musician and film maker has now stood down to allow him to concentrate on 'family commitments'.
Fellow councillor Andy Boddington, who represents Ludlow North said: "I am sorry that Jonny Keeley has needed to stand down as Shropshire councillor to allow him to concentrate on family commitments. He was one of our few young councillors and was a great community champion. I look forward to him returning soon."
The by-election has been called and a formal notice is expected to be published in the next few days.
Mr Keeley is lead singer with ska/rock band Fight the Bear. He has appeared at T in the Park and the band was featured as BBC Radio 1's Tip of the Week and regularly play at venues around the region.