The plainclothes Los Angeles police officer was severely injured in the incident on Thursday in Granada Hills.
The driver abandoned the car and fled the scene, leaving the officer lying on the ground with a major compound fracture to his upper leg and pelvis, police said.
An intensive manhunt followed. At one time, four Granada Hills schools were on lockdown, and residents in a large swath of the city were told to stay inside their homes. After five hours, a man believed to be the culprit was taken into custody.
The officer, who has not been identified, was taken to a hospital, where he is listed in stable condition. LAPD Chief Charlie Beck visited the officer at the hospital on Thursday and said he was recovering.
He said the suspect would likely be booked on suspicion of attempted murder.
Thursday's incident began when the narcotics officer was talking to a man in a red SUV. The officer was between the open door and the doorframe when the driver suddenly accelerated, and he was "trapped by the driver's door," Lt. Andrew Neiman said.
As the SUV careened down the road carrying the officer along, the vehicle hit a tree and narrowly missed another vehicle before the officer fell or jumped.
The driver went "about the length of a football field" before crashing to a halt in the 10900 block of Haskell Avenue, Neiman said.
The lieutenant would not say whether the narcotics officer was taking part in an undercover assignment when the confrontation and crash occurred.
The LAPD's Valley Bureau went on modified tactical alert after the incident, which means officers from prior shifts continue to work. Video from the scene showed the officer being treated by paramedics.
Police set up a perimeter from Woodley Avenue on the west to Haskell Avenue on the east, Index Street to the north and the 118 Freeway to the south.
Schools in the area were locked down briefly as authorities searched for the man, described as a 5-foot-6 black male weighing 190 pounds, wearing blue jeans and a maroon sweater with gray sleeves.
Eventually, a man fitting that description was seen being led away in handcuffs by police officers.