Esler began his career appearing in the popular Australian police drama Blue Heelers and the award-winning ABC Australia made-for-TV movie Curtin. In 2010 Esler appeared in HBO's Tom Hanks, Gary Goetzman and Steven Spielberg-produced and Emmy Award-winning miniseries The Pacific as Private First Class Charles "Chuck" Tatum. After portraying Tatum, he was invited to contribute an afterword to Tatum's World War II memoir, Red Blood, Black Sand, which was used as source material for the series. The book, including Esler's contribution, was re-released by Penguin Publishing in May 2012. He was a series regular for the first three seasons of Hell on Wheels, a Western focusing on the construction of the transcontinental railroad, on AMC, Esler appeared in the role of Sean, an Irish immigrant and ruthless businessman, seeking his fortune in the American West.