Lehane was born in Belfast, Northern Ireland on May 7 1912. Joseph Connolly the senator was his uncle on his mother's side, while Michael O'Lehane the trade unionist was his uncle on his father's side. His family emigrated to Hartlepool in 1912 and then to Dublin in 1920. He was educated at Synge Street Brothers School and University College Dublin, where he studied Law. He became qualified as a solicitor. As a solicitor, he took to defending members of the Irish Republican Army in the Irish Courts. In 1927 he obtained permission for IRA prisoners to speak privately to their solicitors from the Irish High Court. He was active in other Republican and Nationalist circles: He was a member of the Moibhí Branch of Conradh na Gaeilge, and by the 1930s seems to have become active in the IRA itself. In 1931 he was involved in Saor Éire, an attempt by the Irish left-wing to create a communist political party that would have been linked to the IRA. He was a member of the IRA's arms committee and in 1935 he was sentenced to 18 months imprisonment by the Military Tribunal for his membership of the IRA. He was made a commanding officer of the IRA prisoners in Arbour Hill Prison. He married Marie OʼNeill in 1937, whom he would later have a son and two daughters with. He retired from the IRA in April 1938 with Seán McBride as they were not prepared to support the planned bombing campaign in the United Kingdom during World War II, however, he was still interned for a short time in 1939 under the Crimes Against the State Act. In 1940 he was a member of Córas na Poblachta, another attempt to build a Republican political party backed by the IRA.
He was elected to Dáil Éireann as a Clann na Poblachta Teachta Dála for the Dublin South-Central constituency at the 1948 general election. He lost his seat at the 1951 general election. He was a good actor and a keen interest in Irish language theatre. He was one of the leading actors of the Irish Language Theater Company between 1943 and 1958. He was a member of Dublin City Council and of the Citizens for Civil Liberties committee. In 1977 the remains of Frank Ryan, one of the leading left-wing Republicans of the 1930s, were repatriated from Germany, and Lehane delivered the eulogy. He died on 18 September 1983 and is buried in St. Finan's cemetery.
