He emigrated to the United States in 1955, carrying his few possessions and a set of bagpipes (from his time in a pipe band). Arriving in Dover, New Hampshire, Makem worked at Kidder Press, where in 1956 his hand was accidentally crushed by a press. With his arm in a sling, he left Dover for New York to pursue an acting career.

The Clancys and Makem were signed to Columbia Records in 1961. The same year, at the Newport Folk Festival, Makem and Joan Baez were named the most promising newcomers on the American folk scene. During the 1960s, the Clancy Brothers and Tommy Makem performed sellout concerts at such venues as Carnegie Hall, and made television appearances on shows like The Ed Sullivan Show and The Tonight Show. The group performed for President John F. Kennedy. They also played in smaller venues such as the Gate of Horn in Chicago. They appeared jointly in the UK Albums Chart in April 1966, when Isn’t It Grand Boys reached number 22.

Makem left the group in 1969 to pursue a solo career. In 1975, he and Liam Clancy were both booked to play a folk festival in Cleveland, Ohio, and were persuaded to do a set together. Thereafter they often performed as Makem and Clancy, recording several albums together. He once again went solo in 1988. Throughout the 1970s and 1980s Makem performed both solo and with Liam Clancy on The Irish Rovers’ various television shows, which were filming in Canada and Ireland.

In the 1980s and 1990s, Makem was a principal in a well-known Irish music venue in New York, “Tommy Makem’s Irish Pavilion”. This East 57th Street club was a prominent and well-loved performance spot for a wide range of musicians. Among the performers and visitors were Paddy Reilly, Joe Burke, and Ronnie Gilbert. Makem was a regular performer, often solo and often as part of Makem and Clancy, particularly in the late fall and holiday season. The club was also used for warm-up performances in the weeks before the 1984 reunion concert of The Clancy Brothers and Tommy Makem at Lincoln Center. In addition, the after-party for Bob Dylan’s legendary 30th Anniversary Concert Celebration at Madison Square Garden in 1992 was held at the Irish Pavilion.

In 1997 he wrote a book, Tommy Makem’s Secret Ireland and in 1999 premiered a one-man theatre show, Invasions and Legacies, in New York. His career includes various other acting, video, composition, and writing credits. He also established the Tommy Makem International Festival of Song in South Armagh in 2000.

He received many awards and honours, including three honorary doctorates: one from the University of New Hampshire in 1998, one from the University of Limerick in 2001, and one from the University of Ulster in 2007; as well as the World Folk Music Association’s Lifetime Achievement Award in 1999. With the Clancy Brothers he was listed among the top 100 Irish-Americans of the 20th century in 1999.

Makem was married to Mary Shanahan, a native of Chicago, for 37 years, and had four children – daughter Katie Makem-Boucher, and sons Shane, Conor and Rory. They also had two grandchildren, Molly Dewar née Makem and Robert Boucher. Mary died in 2001.

Makem died in Dover, New Hampshire on 1 August 2007, following a lengthy battle with lung cancer. He continued to record and perform until close to the end. Paying tribute to him after his death, Liam Clancy said, “He was my brother in every way.” He is buried next to his wife at New Saint Mary Cemetery in Dover.

A bridge over the Cocheco River on Washington Street in Makem’s long-time home of Dover, New Hampshire, was named the Tommy and Mary Makem Memorial Bridge in 2010.

In 2015 a new Tommy Makem Arts Centre was opened in his home town of Keady.