The 57-year-old Chennithala, a three-time legislator and a four-time Lok Sabha member, will be administered the oath of office by Governor Nikhil Kumar.
"I abide by the decision of the party high command. It was they who asked me to join the cabinet and I have decided to join," Chennithala told reporters at his home district of Alappuzha Tuesday.
As state Home Minister Thiruvanchoor Radhakrishnan Tuesday held a press conference in the capital, and put forward a report of how he handled his portfolio, there were rumours that Chennithala would be given the home portfolio.
The Congress leader, however, shot down the rumours.
"The convention of our party is that it is the chief minister who decides on the portfolio," Chennithala said.
Chennithala earlier offered prayers at the famed Sree Krishna Guruvayoor temple.
Chennithala entered the record books in 1986 when at age 30 he became the youngest minister upon joining the K. Karunakaran cabinet as minister for rural development.
On more than two occasions in the past, Chennithala had declined invitations to join Chandy's cabinet. There were reports that he wanted the home portfolio and also the post of deputy chief minister.
While Chandy was willing to give both, the first demand was shot down by his close aides and the second was obstructed by Indian Union Muslim League (IUML), an ally in the United Democratic Front (UDF) coalition.
The IUML said if there is a post of deputy chief minister, it should be given to it.
On Monday, Union Defence Minister A.K. Antony arrived in the state capital and conveyed the decision to both Chandy and Chennithala that all differences of opinion should be amicably settled.
Meanwhile, Home Minister Thiruvanchoor Radhakrishnan said he was an "obedient party worker" and that he has always worked as per the directive of the party high command.
"Whatever I am told by the party high command, I abide by it. I am happy that under my tenure, the number of major crime cases fell down from 1,498 to 1,129 in this calendar year.
"I have not compromised on bending rules and I have always gone according to the rule of the land," Radhakrishnan said.
Sources close to Chandy told IANS that Radhakrishnan will continue to hold the crucial portfolio of vigilance. He could also be either given the forest or revenue portfolio along with sports.
Meanwhile, UDF convenor P.P. Thankachen said the decision on who will become the new Congress president in the state will be decided after the assembly session ends in February.
--IANS (Posted on 31-12-2013)