During the war years Séamus’ travels were mostly by bicycle and he collected all his tunes by pen and paper.
Séamus found the greatest repository of songs and tunes and their background in fact and fame in a little pocket of North Connemara in a place called ‘Glinnsce’ which translates as ‘Clear Water’ in the English language. He recorded two hundred and twelve items straight from the memory of Colm O'Caoidheain who lived in this area.
The Irish Folklore Commission asked Séamus to focus his attention on the musical heritage Ireland shared with Scotland. This involved him travelling to Scotland in 1946. A bitterly cold winter didn't stop Séamus from swimming every day and he became known locally as the mad Irishman. Séamus said that during his stay on one island, as the weather became colder and colder, more and more people turned out to watch Séamus and his companion from Dublin take their dip. Finally, on the morning they had to break the ice at the water’s edge to bathe, the whole village had turned out to watch whether they’d do it or not. Their clear duty was to uphold the pride of Ireland and take the plunge, but the pub was opened early as a result for all to recuperate.
In 1946 he successfully applied for a job in Radio Eireann as an Outside Broadcast Officer. Commencing this job in August 1947, it wasn’t long before Séamus proved himself to be a skilled presenter. On a renowned visit to Clare in 1949, he recorded the playing of the legendary Willie Clancy, Bobby Casey, Sean Reid, Martin Talty and Micho Russell.
In 1951 Séamus moved to London to work with the BBC on a scheme aimed at recording extensively the surviving folk culture of England, Scotland and Wales. With an uncanny ability to converse in the regional Gaelic dialects with people in Connemara, Donegal, Kerry and even Scotland, he travelled the length and breadth of Ireland and Britain collecting material and was one of the presenters of the radio program "As I Roved Out". He married Margaret Glynn in 1952 and the couple had two children. Daughter Catherine is now a well-known Organist and his son Christopher plays the Fiddle and sings some of his father’s old songs. In 1958 Séamus’ marriage ended and he returned to Ireland where he worked for Radio Eireann as a freelance presenter on programmes such as ‘An Ceoltoir Sidhe’ and ‘Séamus Ennis san Chathaoir’.
Séamus continued to perform around Ireland during the 1960s and played at the first meeting of ‘Na Piobairi Uileann’ in Bettystown, Co. Meath in 1968. In the early 1970s he shared accommodation with Uilleann Piper Liam O'Floinn in Dublin. During that time they formed The Halfpenny Bridge Quartet, with Liam on the pipes, Tommy Grogan on accordion and Sean Keane on Fiddle. Séamus had a lasting impression on Liam O'Floinn who was in awe of his knowledge and expertise. Séamus bequeathed his Uilleann Pipes to Liam. Made by Morris Coyne in the 1830’s, the Pipes were originally purchased by Séamus’ father in a second hand shop in London.