K. J. Yesudas was born at Fort Kochi, in the erstwhile Kingdom of Cochin, into a Roman Catholic Latin Rite family to Augustine Joseph and Alicekutty. His father, who was a well-known Malayalam classical musician and stage actor, was his first guru. Later he joined the R.L.V. Music Academy at Thrippunithura and underwent training. Later he studied at Sree Swati Thirunal music college, Thiruvananthapuram under the late Semmangudy Sreenivasa Iyer. But he could not complete his studies due to financial constraints. For a brief period, he was with Sri Vechur Hari Hara Subramania Iyer, after which he took advanced training from Chembai Vaidyanatha Bhagavatar.In 2011 he completed his 50 Years as a Play Back Singer.

Completed the Ganabooshanam course at R.L.V. Music Academy, Thripunithura, Cochin Graduated from the Sree Swathithirunal Music Academy, Trivandrum Trained under K. R. Kumaraswamy (former principal of the Music College, Kochi),Thripunithura Shri K.C Kalyanasundaram Master, Kunjuvelan Aasan (a disciple of Nadaswara Vidwan Rajaratnam Pillai), Augustine Joseph (his father), Dekshinamoorthi Swamikal V. Dakshinamoorthy, Ramankutti Bagavathar, Sivaraman Nayar, Semmangudi Srinivasa Iyer and Chembai Vaidyanatha Bhagavatar.

The first song sung by Yesudas is Jaathi Bhedam Matha Dwesham (music: M B Sreenivasan) on 14 Nov 1961, which he usually sings on all the special occasions in front of the audience. Yesudas began his career in playback singing in the Malayalam movie Kaalpadukal and Tamil movies in the early 1960s.

He got the first break in his music career with the hit Malayalam film named Bharya ( music by G. Devarajan and lyrics by Vayalar Ramavarma). He sang in Tamil for Bommai first (music: S. Balachander), but the first released movie was Konjum Kumari (music: Veda).

The trio of Salil, Yesudas and Prem Nazir (the evergreen hero of Malayalam Cinema) took the Malayalam Cinema Industry of the 70's by storm. It was generally agreed that Yesudas's voice was the most suited one for Prem Nazir.

In 1970 he was nominated to head the Kerala Sangeetha Nataka Academy and was the youngest person ever to occupy the post.

On 9 Dec 1971, Yesudas missed a flight which later crashed on the way to Madurai. A Hawker Siddeley HS 748 near Chinnamanur was descending into Madurai in reduced visibility. It flew into high terrain about 50 mi (80 km) from the airport, killing the four crew members and 17 passengers.

Yesudas has performed in many major cities around the world. In 1965, he was invited by the Soviet Union government to perform at music concerts in various cities in the USSR and also sang a Russian song over Radio Kazakhstan.Yesudas became one of the senate members in the International Parliament for Safety and Peace.On 14 November 1999, Yesudas was presented with an honorary award by UNESCO for "Outstanding Achievements in Music and Peace" at the "Music for Peace" event in Paris.a concert held to mark the dawn of the new millennium and whose attendees included artistes such as Lionel Richie, Ray Charles, Montserrat Caballé, and Zubin Mehta.

In 1971, during the Indo-Pakistani War, Yesudas travelled all around Kerala with his musical troupe to raise funds for the Indian prime minister's National Defense Fund.

In 2001 he sang for album Ahimsa in Sanskrit, Latin and English and in a mix of styles including New Age and Carnatic. In his music concerts in the Middle East he sings Arabic songs in the Carnatic style. He frequently serves as a cultural ambassador for India through his performances abroad, promoting Indian music.

In 2009 Yesudas began a cross-country musical campaign against terrorism in Thiruvananthapuram, with the motto 'Music For Peace'. Kavita Karkare, wife of Hemant Karkare, handed over the torch to Yesudas to mark the launch of the 'Shanthi Sangeetha Yatra'.

Yesudas is married to Prabha. They have three sons, Vinod, Vijay and Vishal. The second son Vijay Yesudas is a budding musician who won the Kerala State Film Award for Best Male Playback Singer in 2007 and 2013. The family is currently settled in Chennai and Trivandrum. He also owns estates in Fort Lauderdale, Florida, USA and Flower Mound, TX, USA for personal and business reasons.

Sree Narayana Guru’s great message, One religion and One God for all humanity", influenced young Yesudas in his dealings with his fellow men. He had his own heroes among the musicians too. Mohammed Rafi, Chembai Vaidyanatha Bhagavatar and Balamurali Krishna are the ones he admires the most.

For the past 30 years Yesudas has been visiting Kollur Mookambika temple, Udupi, Karnataka on his birthday to sing keerthans of Saraswati devi, the Goddess of knowledge, music and the arts. The music festival started on his 60th birthday. The nine-day music festival begins every January at Kollur Mookambika Temple. On Sunday, 10 January 2010, he celebrated his 70th birthday (Sapthathi) at Kollur Sri Mookambika Temple with 'Sangeetharchana' (classical devotional songs), along with 70 singers before goddess Mookambika. The Sangeetharchana included "Pancharatna Gayana" of Thyagaraja's poems. He also took part in the Vidyarambha function. All India Radio broadcasted the special Sangeetharchana all over Kerala.