Jurors, who deliberated for 2 1/2 days, convicted Ryan Allen Jones of attempted voluntary manslaughter, assault with a deadly weapon and battery. They acquitted him of two counts of attempted murder.
The 35-year-old faces more than 20 years in prison when he is sentenced April 22.
Deputy District Attorney Steven Schott told the jury that Jones -- who was convicted of battery on a peace officer in 2008 in Oakland -- set upon firefighters Ben Vernon and Alex Wallbrett in a "brazen attack that was nothing short of pure violence.''
The prosecutor said Vernon and Wallbrett were among several firefighters who responded to a late afternoon call of a sick and drunk man at the trolley station in the 500 block of Park Boulevard.
Schott said Jones refused orders to step away from the scene, then attacked two transit officers before stabbing the two firefighters.
The prosecutor said Vernon jumped over a rail to assist the transit officers and was stabbed twice with a 3-inch pocket knife, suffering a punctured lung.
The defendant also tried to stab Vernon in the head but missed, according to the prosecutor, who said Jones stabbed Wallbrett multiple times.
A fire captain tripped as he pushed the defendant over a concrete bench, prompting Jones to declare, "I will kill you all,'' according to the prosecutor.
Vernon testified during a preliminary hearing last year that Jones was helpful at first, saying the sick and drunk man had been yelling about mixing his medicines before a 911 call was made.
Vernon said he was tending to the drunk man when he saw Jones run into two transit security officers, sending all three over a rail. Vernon said he jumped over the rail when he saw Jones punching one of the officers.
The firefighter said he saw Jones reach into his back pocket and before he knew it, he was stabbed twice.
Transit security officers ended the assault by pulling the 6-foot-3, 210- pound assailant off the victims and dousing him with pepper spray. The guards then held Jones until police arrived.
Defense attorney Thomas Barr said Jones was waiting at the trolley stop when he noticed a confrontation between a transit officer and the drunk man. Barr said Jones was trying to help and keep the situation calm when fire Capt. Steven Michaels pushed him over a bench, forcing Jones to defend himself.
"Mr. Jones was acting as a good Samaritan,'' Barr told the jury.
Barr said Jones wasn't encroaching on the firefighters until Michaels called him over and incited the incident.
Barr said Michaels -- who faces allegations that he punched his pregnant wife and kicked down the door of a girlfriend -- has a temper "that got the best of him.''
The defense attorney said Jones was thrown over a rail, hit his head and was blinded by pepper spray.
Jones felt in danger and pulled out a knife in the six-on-one melee and thought, "I don't want to be another statistic,'' Barr told the jury.
Barr said Michaels didn't follow his duties and the firefighters who were injured "had a duty to stand back.''
"This is a case of perfect self-defense,'' Barr said.