Career
Born in Cork, Lenihan began his career with College Corinthians. He moved to Cork City in July 2012, making a total of 27 League of Ireland appearances for them. After receiving interest from a number of English clubs, he signed for Hull City on 31 August 2014.
The transfer fee was believed to be £200,000.
He signed a one-month loan deal with Blackpool in November 2014. He made his debut on 8 November 2014 in a 3–1 away defeat to Leeds United.
He returned to Hull on 25 November after sustaining a knee injury. Lenihan represented the Republic of Ireland under-19s.
Lenihan made his debut for the Republic of Ireland under-21s in May 2014.
He was called up to the senior squad in November 2014. However later that month he was sent back to the under-21s.