Graeme Reid was trapped in his Hyundai Sonata for more than an hour after it went over the wall and entered the water. The 42-year-old was unable to get out of the vehicle after it dropped to the bottom of Peterhead Harbour on Monday morning.
Yesterday his wife Carolyn and two stepchildren, Amanda and James, paid tribute to the taxi driver. They described him as a "cherished" husband and a "loving" grandad to his three grandchildren.
The accident happened at Peterhead Harbour at about 8.50am. The car was seen heading down Ellis Street and over the Seagate.Onlooker Gavin Sutherland jumped into the water shortly after the car went over the wall but could not reach it.
The 33-year-old offshore worker said: "I tried several times to get down to it but I just couldn't do it - it was a bit deep and cold and there was zero visibility.
"My thoughts are with the family - it's such a shame."
Coastguards and lifeboat crews struggled for more than an hour to attach a rope to the vehicle and haul it out of the water. It was eventually winched up on its roof on a nearby slipway.
Mr Reid worked as a driver for Grab-A-Cab, based on the Seagate road which borders the busy harbour.
Rauri McLean, who works at Grab A Cab, said he had been friends with Mr Reid, who lived in Peterhead, for 15 years.
Mr McLean said: "Working as a taxi driver was his life.
"Even when he was supposed to be off we had to chase him to go home and nothing was ever too much bother for Graeme."