Officers were called to a disturbance in Clyde Street in Glasgow city centre at around 4.15am on Thursday.
The man was then seen running along the street before jumping into the River Clyde by the South Portland Street Suspension Bridge.
Despite attempts to rescue him, his body was recovered a short time later.
A police spokeswoman said: "Around 4.15am this morning, police were called to a disturbance in Clyde Street, Glasgow.
"On arrival, a man was seen running off along Clyde Street before jumping into the water near to the suspension bridge.
"Officers, assisted by other emergency services, tried to rescue the man but were unable to do so.
"His body has since been recovered. Inquiries are continuing and a report will be sent to the procurator fiscal."
The coastguard and Scottish Fire and Rescue Service (SFRS) also attended.
A SFRS spokesman said: "The Scottish Fire and Rescue Service was called at 4.20am on Thursday July 4 to assist emergency service partners at Clyde Street, Glasgow.
"Operations control mobilised two appliances and two water rescue units to the scene. Crews left at 6.42am."
A spokeswoman for the Coastguard added rescue teams sent were from Greenock and Helensburgh after police requested their help around 4.30am.