Born on April 6, 1810, the youngest of three sons of Joseph and Lucy (Smith) Sears, Edmund grew up on a farm within sight of the Berkshire Hills, in Sandisfield, Massachusetts. Sears attended Union College, in Schenectady, New York, where he was a member of the Delta Phi fraternity. Following graduation from Union in 1834, Sears studied law for nine months under a lawyer in Sandisfield. He attended Harvard Divinity School, graduating in 1837 and began to preach as a missionary in Toledo, Ohio, remaining nearly a year. He served the Greater Boston Unitarian congregation in Wayland, and then a larger congregation in Lancaster. After seven years of hard work, he suffered a breakdown and returned to Wayland. He wrote "It Came Upon the Midnight Clear" while serving as a part-time preacher in Wayland.