"Get Happy" is a term used in the African American Gospel Music tradition, that refers to the experience of receiving the Holy Spirit during a Church service, usually involving ecstatic singing, or during prayer, or spontaneously.

Accounts of nineteenth century African American slave spirituality use the term, as recorded in the book "God Struck Me Dead, Voices of Ex-Slaves" by Clifton H. Johnson ISBN 0-8298-0945-7:

"All of my people were great Christians. Shouting, singing, praying, and good old heartfelt religion make up the things that filled their lives. ... Aunt Charlotte used to cry most all the time when she got happy." - an ex-slave preacher, in "God Struck Me Dead", page 75.

One of the early nineteenth century traditional 'Negro Spirituals ' to use the phrase, is the following [1]:

GOOD MORNING EVERYBODY

Good morning everybody

Good morning everybody, Lord

My soul got happy this morning

My soul got happy this morning, Lord

You may call me “hypocrite member”

You may call me “hypocrite member”, Lord

But my soul got happy, this morning

But my soul got happy this morning, Lord

I’m going to see my mother

I’m going to see my mother, Lord

Going to sit down by my Jesus

Going to sit down by my Jesus, Lord.

For other examples of such gospel music see the following:

"Say Amen Somebody" featuring Thomas A. Dorsey on DVD video (ASIN B0000560)

"Greatest Gospel Hits" by Shirley Caesar (ASIN B0000AVHA1)

"Get Happy" was a popular tune drawing on this tradition, with words by Theodore Koehler and music by Harold Arlen. It was performed by Ruth Etting, Nat Shilkret , and Frankie Trumbauer in 1930, Frank Sinatra and Judy Garland in 1950, and Ella Fitzgerald, Jane Froman and Susan Hayward in 1952.

"Get Happy" is also the title of a CD by the musician Elvis Costello (ASIN B0000B1A5O), possibly inspired by the Gospel music use of the term, but not containing any Gospel music per se.