While Mr Coe won't formally resign until next month, Thursday was his final sitting day in the ACT Legislative Assembly.

It marked the end of a 12-year career in ACT politics, which Mr Coe said had "flown by".

The 37-year-old was targeted throughout his political career for his social conservative views, with Andrew Barr and Labor sharpening their attacks on the then-Opposition leader ahead of last year's October election.

Some critics and political observers cited the conservatism of the Canberra Liberals as one of the key reasons behind their bruising defeat, the party's sixth-straight election loss.

In his parting message, Mr Coe said all political views were "valid and deserved to be respectfully heard and considered".

"I think many people on the right of politics can understand why some people are left wing. We disagree, but we understand," he said.

"Unfortunately, I think there are many in the left who do not understand or comprehend why someone would be in the right."

The Yerrabi MLA said his 12 years in ACT politics had made him more "confident and vigilant" about the importance of "protecting and welcoming" input from people of faith in public debate.

He praised Canberrans who voted and stood up for his party, repeating a line he's used regularly - "to be a Liberal in this city is tough".

Mr Coe announced plans to retire from politics late last month, conceding he no longer had the drive to fully commit to the job after the Liberals' election loss.

The Canberra Times this week reported that Mr Coe had been reprimanded after an investigation into alleged use of his office's printer for political purposes ahead of October's election.

The ACT's Commissioner for Standards found that it could not be proven that Mr Coe knowingly used Assembly resources for political purposes, and that it could have been a simple oversight. However, he found the former leader had failed to act with diligence and transparency.

In correspondence made public this week, Mr Coe said his struggles with mental health had contributed to the delays in him responding to the investigation and would be the reason he left politics.

Mr Coe has since said that he no longer attributed his departure from politics to his mental health.

"With the passage of time, I'm in a much better headspace," Mr Coe said after the report was published.

"I've been able to consider a lot of other factors and I know that now is the right time for my family and me to start a new chapter.

On Thursday, Mr Coe become emotional as he thanked his wife Yasmin, before breaking into a smile as he described how he looked forward to recounting his time in politics to his two young children when they grew up.

While admitting there were "no shortage of frustrations" in spending an entire career on the opposition benches, Mr Coe said he took pride in his achievements, including his work uncovering the government's controversial land deals.

"I know now is the right time to move on from this place," he said. "I have a fear that if I were to stay it could turn into a job, rather than a calling."

Mr Coe urged all parties to do what they could to make Canberra a more affordable place to live.

He will remain in the Assembly until the end of budget estimates early next month, before handing in his resignation.

His departure will trigger a countback of votes in the seat of Yerrabi, which is likely to see former Liberal parliamentarian James Milligan returned to the Legislative Assembly.