It has been a long time since Barry O'Farrell had a holiday of more than a week with his family.

Amid the public firestorm of the alcohol-fuelled violence debate in February, the Premier slipped out of the city to speak to Dubbo voters, lamenting to his bush audience he missed two-week holidays, and even a trip to his beloved footy involved police tagging along.

Suddenly, Mr O'Farrell has cut himself loose from the state's highest office. The main gate of the Wests Tigers football stadium beckons, and a trip booked to walk Kokoda with his youngest son in July holds greater promise for the Liberal member for Ku-ring-gai.

In an email to colleagues within hours of his resignation, Mr O'Farrell said he would continue to serve on the parliamentary team. Whether that stretches beyond the March 2015 election is the big question. Mr O'Farrell, 55, would mark 20 years in Parliament next year.

Former Liberal premier Nick Greiner, himself deposed by ICAC, said of Mr O'Farrell's decision to leave: "His judgment was political, rather than going to the substance of the ICAC finding."

Political instinct had kept Mr O'Farrell in the NSW leadership for the past seven years, serving as deputy leader for seven years before that. He was rewarded with preselection for Bruce Baird's seat of Northcott in 1995, after three years as the NSW Liberals chief tactician as state director. His wife Rosemary was Mr Baird's personal assistant, and the daughter of the former federal Nationals MP Bruce Cowan. With a stint also served in John Howard's office, Mr O'Farrell's working career has revolved around the Liberal Party.

Mr O'Farrell's testimony at ICAC over the bottle of wine was peppered with references to his obsessive diet and fitness regimen as Premier. His rise from opposition leader to government was accompanied by a massive weight loss, which continued once in office. He exercised six days a week, avoiding alcohol and banning carbohydrates at dinner.

His gym routine was detailed to ICAC on Tuesday: 5.30am starts, twice a week with a personal trainer and twice a week in the Parliamentary gym on his own. O'Farrell remembered this as crucial detail, but not the thank you note for the wine that lost him his premiership.

The image of the newly-elected Premier quaffing vintage Grange jars with the everyman O'Farrell had been careful to portray. He once told reporters he lived for a time in a Housing Commission estate in Melbourne, after his father left the army. The family settled in Darwin, but had their home destroyed by Cyclone Tracy in 1974, losing everything.

As Premier, Mr O'Farrell had early on been seen as a moderate, setting up an inquiry into why race hate laws in NSW weren't working with a view to toughening them.

He raised hopes on same-sex marriage by establishing an inquiry that found states had the legal right to pass same-sex marriage laws.

But political instinct took over, and Mr O'Farrell spoke out against a NSW bill on the day it was to be voted on in the NSW Parliament, deferring to the newly elected Liberal Prime Minister Tony Abbott, who wanted the matter dealt with at a Commonwealth level.

As talkback radio continued to pillory the government for going soft on crime, one year out from an election, Mr O'Farrell suddenly went tough, proposing seven mandatory prison sentences.

Mr O'Farrell negotiated directly with the minor parties in the upper house with mixed success. The support of avowed anti-gambling campaigner Reverend Fred Nile was won for James Packer's Barangaroo casino. But the relationship with the Shooters and Fishers Party has soured significantly, after Mr O'Farrell sided with the public, who opposed the Shooters original deal to allow recreational shooting in 79 national parks.

Upsetting the Shooters cost the government the opportunity to have its controversial planning legislation passed, and has seen Mr O'Farrell's mandatory sentences for alcohol violence blocked in the upper house.