The victim was known to police, who are investigating whether the attack was linked to organised crime or some other conflict, NSW Police Acting Superintendent Ben Kennis said on Tuesday.
The 32-year-old was stabbed on Marrickville Rd at Marrickville, in Sydney's inner west, about 7.30pm on Monday.
Paramedics treated the man but he died at the scene.
"It was not a random attack on Marrickville Road, the community can be assured of that," Supt Kennis said.
The busy main street in Sydney's inner-west is lined with restaurants, some of which had to close their doors for the night after the attack.
The man was dining with several others at one of them before he was stabbed.
"Family and friends did converge," Supt Kennis said.
"It was a highly emotive crime scene at the time, but I can't say with any certainty how they found out about what happened."
One man breached the crime scene and had to be restrained and an officer drew their taser but did not deploy it, he said.
Supt Kennis said the victim had met up with another person, who he appeared to know.
"That encounter did not last long, until the male was stabbed," Supt Kennis said.
But police are yet to identify the person spotted on CCTV fleeing down Silver Street after the attack.
Police are appealing for more footage as officers, including riot squad police, examine the scene.