After three hours of uncertainty, a visibly fatigued Menon, 32, emerged from captivity at 6.30 p.m. accompanied by Maoist mediators in Tarmetla, a tiny forested hamlet.
His release sparked off celebrations by his family here in Sukma town as well as in Tamil Nadu where his parents live. The Chhattisgarh and the central governments also heaved a sigh of relief.
His pregnant wife Asha, who is in Sukma, said she was relieved.
In a significant comment, Chief Minister Raman Singh described the release as a "first step toward achieving peace with the Maoists in the state".
Singh, who spoke briefly to Menon, said he had asked the IAS officer from Tamil Nadu to first rest.
Menon, who was wearing a blue shirt and carried a black bag on his right shoulder, expressed gratitude to the government and his colleagues for his safe release.
An asthma patient, he said he was feeling "ok". Badgered by questions from journalists, Menon pleaded that he was tired and would speak the next day.
He is to spend the night at a Central Reserve Police Force (CPRF) camp at Chintalnar, 80 km from Sukma town.
Would he serve as Sukma district's collector again? Yes, he answered, "if the state government wishes".
Menon was abducted from a forested area in the Bastar region of Chhattisgarh April 21. The Maoists took him away after murdering his two bodyguards Amjad Khan and Kishen Kujur.
He is believed to have been held by Maoists deep in a forest, amid multiple layers of security.
Uncertainty had clouded Menon's release Thursday after some reports said he had been released in the afternoon.
For a few hours, there was no sign of the collector. It was only in the evening that Maoists SMSed journalists waiting at the Chintalnar CRPF base camp, asking them to proceed to Tarmetla, four kilometres away.
Maoist mediators G. Hargopal and B.D. Sharma had gone to receive Menon somewhere at the edge of a landmine-protected hideout in Tarmetla, located more than 500 km south of state capital Raipur.
Tarmetla is where Maoists killed 76 paramilitary personnel in April 2010.
Earlier, Menon's father A. Varadhas, based in Tamil Nadu's Tirunelveli town, thanked the Chhattisgarh and central governments, the mediators and rebels for releasing his son.
He also appealed to Maoists not to resort to abductions again. Varadhas told IANS: "We are all really happy."
Menon's release was ensured after Maoist interlocutors and government mediators Nirmala Buch and S.K. Mishra signed a two-page agreement Monday night.
In line with the pact, a high-power committee will be set up to look into all demands made by the Maoists.
These include considering the release of Maoists jailed allegedly on fake charges.
The panel is to become functional within an hour of Menon's release.
Menon's sister Juliet Ruby told IANS from Mysore: "We are discussing whether to go to Chennai or Chhattisgarh. It depends on my brother's plan, whether he is coming to Chennai or staying there.
"It also depends on his wife Asha's health. She was advised by doctors not to travel."