Premier Will Hodgman will go down in history as the second longest-serving Liberal premier when he retires from politics.
Despite last month telling journalists that he had no intention of relinquishing the leadership, Mr Hodgman, 50, on Tuesday announced he intended to do just that next week.
He said he had arrived at a final decision over the weekend following reflection on his future with his family over the Christmas period.
Mr Hodgman said it was then he had resolved that he was unlikely to recontest the next election.
He said a decision to leave mid-term would give the party a chance of renewal and the new leader the opportunity to lead it to the 2022 election.
"I have given the job everything," he said.
"But I believe it is the right time for someone else to do it.
"I leave the job with Tasmania now a much better place than when we started."
Mr Hodgman said he had been a politician for the entirety of his children's lives.
"Our children have grown up with me in the public spotlight and often it hasn't been easy," he said.
"There is no denying that this job can have an impact on your personal life but we have done it together and they have supported me all the way."
Mr Hodgman said he had not yet decided on his future plans.
"I have no job to go to," he said.
"I've always said I would give this job 100 per cent and I wouldn't be doing so if I was thinking about what my next one might be."
Mr Hodgman cited the state's economic turnaround, as well as reforms in education and family violence, as some of the achievements of which he was most proud.
Mr Hodgman entered Parliament in 2002 with Jeremy Rockliff, 49, and Peter Gutwein, 55.
He described the trio on Tuesday as part of a triumvirate - Latin for a political regime dominated by three powerful men.
Mr Hodgman was named Opposition Leader when Rene Hidding retired from the position following the 2006 election.
Mr Hodgman missed out on serving as Premier following the 2010 poll which delivered a hung parliament.
This resulted in Governor Peter Underwood asking then-Labor Premier David Bartlett to test his numbers on the floor of the house.
Labor eventually won government with support from the Greens.
Mr Hodgman eventually led his party to a convincing win in 2014 with the Liberals occupying 15 of the 25 seats in Parliament.
The margin between the opposition parties was narrowed in the 2018 ballot when the party returned as a one-seat majority.
This was the second time in the party's history that it had been elected in a majority for a second term.
Mr Hodgman's announcement of his intention to resign means he will not overtake Robin Gray, who served from 1982 to 1989, as the longest-serving Liberal premier in Tasmania.
He will, however, have beaten Sir John McPhee's tenure by one month, who served from 1928 to 1934.
Mr Hodgman's second term in government as the leader has not been as smooth as the first.
He was blindsided by Labor and the Greens' nomination of Sue Hickey as House of Assembly Speaker which she accepted.
The relationship between Ms Hickey and the government became fractured when it was forced to negotiate with her over several issues or wear the consequences of her crossing the floor on legislation.
After being passed over for a ministerial position for a second time, Ms Hickey threatened to leave the party last year.
In the same year, two members of government - Adam Brooks and Rene Hidding - resigned which triggered recounts.