The son of Jackson Munya M'Rukunga and Grace Mwakithi, he was born and raised in Muthaara, Meru County.

In 1993 he graduated with a Bachelor of Law degree (LLB 2nd class Hons Lower Division) from the University of Nairobi.

In 1997 he was published in the Boston University International Law Journal, under the title "The Role of the Organization of African Unity in Conflict Resolution and Dispute Settlement in Africa".

He was published in the Moi University Journal in 2002 under the title "The Role of the International Court of Justice in Resolving African Disputes: Past, Present and Future Prospects".

He was also a member of the Health Club Management committee and the Parliamentary Investment Committee (PIC) before his appointment to the government in 2006 as the Assistant Minister, Ministry of Internal Security and Provincial Administration, where he called for stronger laws to curb small arms proliferation.

The Supreme Court quashed the earlier ruling on 31 May 2014, stating that the burden of proof lay on the petitioners, and reinstated him as Governor of Meru.

[9] During the 8 August 2017 election, Munya was defending his gubernatorial seat against his rival, former Meru County Senator, Kiraitu Murungi.

Following the disputed 2017 presidential elections where the Supreme Court declared the presidential elections null and void, Munya, suspecting mischief in his poll loss to former ally turned bitter foe Kiraitu Murungi, launched a poll petition challenging his loss.