My Jesus I Love Thee is a poem written by William Ralph Featherston around 1864. Featherston is said to have been either 12 or 16 years old when he wrote the poem. In 1876 Adoniram Gordon added music to it. Featherston died at the age of 27, well before his poem had become a well-known inspirational hymn. The poem is believed to have been Featherston's only publicly published work.

According to Tim Challies,
Not much is known about Featherston, except that he attended a Methodist church in Montreal, that he was young when he wrote the poem (12 or 16 years old), and that he died at just 27 years of age. One story about how the poem became public is that Featherston mailed it to his aunt in Los Angeles who, upon reading it, quickly sought its publication... It wasn’t until several years after Featherston’s death that Adoniram Judson Gordon (founder of Gordon College and Gordon-Conwell Theological Seminary) added a melody and published it in his book of hymns, thus forever transforming this poem to a song.

(http://en.wikipedia.org/wiki/My_Jesus_I_Love_Thee)

A Protestant Episcopal Bi­shop of Mi­chi­gan once re­lat­ed the fol­low­ing in­ci­dent to a large au­di­ence in one of the Rev. E. P. Ham­mond’s meet­ings in St. Lou­is. “A young, tal­ent­ed and ten­der-heart­ed ac­tress was pass­ing along the street of a large ci­ty. See­ing a pale, sick girl ly­ing up­on a couch just with­in the half-open door of a beau­ti­ful dwell­ing, she en­tered, with the thought that by her vi­va­ci­ty and plea­sant con­ver­sa­tion she might cheer the young in­va­lid. The sick girl was a de­vot­ed Christ­ian, and her words, her pa­tience, her sub­mis­sion and hea­ven-lit coun­te­nance, so dem­on­strat­ed the spir­it of her re­li­gion that the ac­tress was led to give some ear­nest thought to the claims of Christ­i­an­i­ty, and was tho­rough­ly con­vert­ed, and be­came a true fol­low­er of Christ. She told her fa­ther, the lead­er of the the­a­ter troupe, of her con­ver­sion, and of her de­sire to aban­don the stage, stat­ing that she could not live a con­sis­tent Christ­ian life and fol­low the life of an ac­tress. Her fa­ther was as­ton­ished be­yond mea­sure, and told his daugh­ter that their liv­ing would be lost to them and their bu­si­ness ru­ined, if she per­sist­ed in her re­so­lu­tion. Lov­ing her fa­ther dear­ly, she was shak­en some­what in her pur­pose, and par­tial­ly con­sent­ed to fill the pub­lished en­gage­ment to be met in a few days. She was the star of the troupe, and a gen­er­al fa­vo­rite. Ev­ery prep­a­ra­tion was made for the play in which she was to ap­pear. The ev­en­ing came and the fa­ther re­joiced that he had won back his daugh­ter, and that their liv­ing was not to be lost. The hour ar­rived; a large au­di­ence had as­sem­bled. The cur­tain rose, and the young ac­tress stepped for­ward firm­ly amid the ap­plause of the mul­ti­tude. But an un­wont­ed light beamed from her beau­ti­ful face. Amid the breath­less si­lence of the au­di­ence, she re­peat­ed:

‘My Jesus, I love Thee, I know Thou art mine;
For Thee all the follies of sin I resign;
My gracious Redeemer, my Saviour art Thou;
If ever I loved Thee, my Jesus, ’tis now.’

This was all. Through Christ she had con­quered and, leav­ing the au­di­ence in tears, she re­tired from the stage, ne­ver to ap­pear up­on it again. Through her in­flu­ence her fa­ther was con­vert­ed, and through their unit­ed evan­gel­is­tic la­bors ma­ny were led to God.”

(http://www.hymntime.com/tch/htm/m/j/e/mjesusil.htm)