He is best known as the showrunner and executive producer of Modern Love on Amazon Prime Video, for his films Once, Begin Again, and Sing Street.

In addition to shooting music videos, Carney also wrote and directed two award-winning short films (Shining Star and Hotel) before making his first feature.

[2] The low-budget drama, shot in black and white, tells the story of two couples whose relationships begin to crumble over an eventful weekend.

He co-wrote and co-directed (with his brother Kieran Carney and Tom Hall) the successful RTÉ TV series Bachelors Walk.

A story about an escaped convict who fools a whole Irish village into thinking he's a visitor from outer space, the film starred Simon Delaney and Cillian Murphy, Zonad was extremely low-budget and was never released.

A music drama, the movie stars The Frames frontman Glen Hansard and Czech musician Markéta Irglová.

Carney attracted criticism in 2016 when he referred to Keira Knightley in an interview with the UK's independent newspaper, stating "I'll never make a film with supermodels again."

Knightley, who has amassed multiple accolades throughout her career, including Oscar, Golden Globe, BAFTA and SAG Award nominations, worked with Carney on the film Begin Again, alongside Mark Ruffalo and Adam Levine.

In March 2022, it was announced that Carney would replace Kenneth Branagh as the director of an untitled Bee Gees biopic for Paramount Pictures.