Yemm was born in Berkshire to a musical family, and began studying piano, organ and singing at age nine.
[1] He proved a capable concert organizer as well as an organist,[7] and had a good reputation as one who gave his services free to charitable and religious events.
[1] One remarkable concert was in celebration of the Foreign Bible Society's 50th anniversary, where among other musical duties, Yemm conducted the 300-member choir.
[8] He left Chalmers in March 1910 for St. Laurence's (Dominican Catholic) Church, Buxton Street North Adelaide, where a new organ had recently been installed.
[10] He gave a series of free Sunday Grand Organ recitals at the Town Hall in conjunction with elocutionist Clement May in July and August 1912 during the absence of W. R. Knox, who instituted the tradition.
[11] South Australian troops returning in February 1915 from the capture of German New Guinea received no official welcome, as no-one knew they were coming, but the "Cheer-ups" made up for it with a reception held at their great tent near the Adelaide railway station on 12 March.
Musical entertainment was provided by Yemm and some of the top artists of the day: Ethel Ridings, Gladys Cilento, and Professor Charles Sauer.
[12] He was musical director at the Cheer-up farewell on 11 September 1915 to a record 750 reinforcements for the 10th, 12th, 16th, and 27th Battalion and the 3rd, 9th, and 11th Light Horse leaving for the front.
Percy Scragg, advance agent and publicist, and Louis W. Yemm, piano, musical director, which toured country towns in 1917: Barely a week went by that Yemm was not playing piano or organ at some patriotic function, usually Cheer-ups, and was directing three or four major entertainments a year until 1920 when the last contingent of South Australian soldiers returned home.
In 1921 a large number of patriotic organisations combined to continue the event as the "Violet Memory Day", generally held on the nearest Sunday to 4 August, anniversary of Britain's (and therefore Australia's) declaration of war.