Gitari was born in Ngiriambu in Kirinyaga County to Samuel Mukuba, who was an Anglican Evangelist, and Jessie Njuku.
Gitari studied at the Kangaru High School, in Embu, and at the University of Nairobi, where he obtained a Bachelor of Arts degree.
Gitari tenure at the Dioceses of Mount Kenya East and Kirinyanga witness an amazing growth of membership, due to his Evangelicalism.
He led many missions in Kenyan universities and also promoted the development, theological education, liturgical renewal and women's ordination to the priesthood.
Gitari pastoral work led to political controversy, since he felt it was his duty to preach against land grabbing by powerful politicians and economic injustice.
During his tenure, he worked to create peace and unity in the church and to solve the divisions and quarrels at their dioceses, since several did not have bishops due to allegations of nepotism and tribalism, often related to political influence.
Along with other fellow clergymen such as Njoya, Okullu, and Muge, Gitari had the courage to criticize and hold the government accountable for its actions.
Through the power of the spoken word, Gitari scared politicians and quelled the storm of social lies proclaimed by those whose interest was to enrich themselves at the expense of the poor.