A murder investigation has been launched into the death of Christopher Warren, who is from St Teresa's Gardens in Dublin.
After he was shot, a C180 blue Mercedes car dropped him off at St James' Hospital at around 7pm yesterday evening.
He died shortly afterwards from his injuries.
The blue car was later found abandoned around Cork St shortly afterwards and Gardaí are appealing for anyone who may have witnessed it to contact them.
Gardaí are also particularly interested in speaking to anyone who witnessed or heard anything suspicious in the Constitution Hill area of Phibsborough - especially Great Western Way, the lane leading from Great Western Way to the Royal Canal Bank, Auburn St and the junction of Great Western Way - to contact them.
A post-mortem is currently taking place on the body of the man, who was known to Gardaí.
A man in his 20s has been arrested in connection with the incident and is being held at Kevin Street Garda Station.