Firefighters were called to the 2900 block of Sunburst Drive around 10:10 a.m., according to the San Jose Fire Department, which first reported the incident on social media.
Crews shut down the residential street as they worked to reach the worker, who was suspended high in the tree and unable to descend.
About a half-hour later, the department said a helicopter from Cal Fire was en route to assist with the rescue.
Video later released by the fire department shows the helicopter crew lifting the worker from the tree and lowering him safely to the ground.
The worker’s identity and the cause of the medical emergency were not immediately known. Authorities said he was taken to a local hospital and is in serious condition.
No other injuries were reported.
The rescue temporarily closed Sunburst Drive and drew emergency crews to the neighborhood as officials urged residents to avoid the area.