Mr Walker recently stepped down as the National Party’s candidate in the Southland seat, after admitting he released private details of Covid-19 patients to media.
He will not contest the September 19 election and has been granted leave from Parliament.
Because he has not quit or been sacked, he will still receive three months' pay from the taxpayer totalling $60,000.
Mr Walker went to ground after his indiscretion became public and has not spoken to media.
However in a Facebook post tonight, Mr Walker included a long list of what he said were "just a few" of his achievements.
Among the 40-strong list were: "Fighting for farmers who are battling never-ending rules and regulations", helping with "many immigration cases", "protesting the decision to downgrade the Lumsden Maternity Centre" and "presenting Blair Vining’s petition for better cancer care".
He also said he'd also brought "democracy to Gore", by hosting a select committee to hear from submitters on the Otama Water Scheme Bill, celebrated winter by taking part in the Bird Man competition and even "Cancelling my honeymoon to fight for [the survival of farm institute] Telford".
Mr Walker said he had travelled over 160,000km and assisted more than 2500 constituent cases during his term.
He ended his post by saying: "I believe I have worked hard throughout my time as the MP and have given this role my everything.
"Thank you so much to everyone who has supported me."
