He has also served as the chairperson of the ruling party (United Democratic Alliance) affiliated to President of the Republic of Kenya Dr William Ruto.

Before joining the ruling party, Muthama played a critical role in National Super Alliance (NASA) and CORD in 2013 and 2017, respectively.

During the Kenya Kwanza campaigns in 2022, he was drawn to the President's agenda of the bottom up economic structure to support the common mwananchi.

Muthama's mining firm Rockland Kenya Limited trades in ruby red and green garnets.

Muthama once served as former ruling party KANU Vice Chairman in the larger Machakos District.

He decided not to vie for a second term in solidarity with those who the wiper party had mistreated & denied them certificates after a shamble nomination process .

Muthama and others including David Musila were instrumental in negotiating for a coalition between retired President Mwai Kibaki and Wiper Leader Stephen Kalonzo Musyoka who became Vice President to calm tension after chaos erupted following the controversial 2007 Presidential elections before the Grand Coalition government was formed with ODM Leader Raila Odinga being appointed Prime Minister.

This is reported to play out in what is considered a supremacy battle for control of Kenya's lower eastern voting block in Ukambani.

[13] While criticizing the BBI initiative in January 2020, Muthama requested President Uhuru Kenyatta to resist the temptation to cling on to power beyond his second and final constitutional term in 2022.

In June 2016, Senator Muthama was among Eight Kenyan politicians arrested for alleged hateful public utterances.

Muthama and his colleagues were protesting the surveying of the land parcel for allocation to squatters who hailed from Nairobi.

Muthama is also enjoined in a legal dispute on the ownership of the land between the KBC and the Komarock Ranching and Farming Cooperative Society.

[33][34] In December 2018, Muthama announced his intention[35] to vie for the Machakos County Governor Position at planned 2022 General Elections in Kenya.