Shadow Home Affairs Minister Jonno Duniam has announced his intention to leave parliament later this year.
The 43-year-old has been in the Senate for 10 years representing Tasmania.
Senator Duniam told the ABC he has been weighing the decision for some time.
"After much consideration, my family and I made the call that it was time for me to be home more," he said.
"It was a tough call, after 25 years in and around politics."
He told Opposition Leader Angus Taylor of his decision a few weeks ago.
"Angus knew some weeks ago and I gave him a commitment I will do what needs doing to finish the job he has asked me to do."
Senator Duniam will leave parliament later this year, requiring a reshuffle of the shadow ministry.
In a statement, Senator Duniam acknowledged the "difficult timing", as the Liberal Party works to rebuild while trying to fight off concerns surrounding the rise of One Nation.
"But I am confident that my friends across both the Liberal Party and the National Party are firmly on the right path," he said in his statement.
"No two people in the Coalition are more equipped to lead us (and Australia) back to success than Angus Taylor and Matt Canavan; they are both outstanding leaders and have a love for our country that is unrivalled."
Reacting to the news, Home Affairs Minister Tony Burke said the Liberal Party was losing one of its "best and brightest".
"There'll be plenty of times when Senator Duniam and I are sparring, and he'll say some pretty harsh things, as you'd expect the shadow minister to say, but the reality is, whenever there's been something squarely in the national interest, I've never seen him be anything other than professional," he told Sky News.
The announcement comes days after Tasmanian Liberal senator Wendy Askew's decision to retire.
