Born in Helsinki, Finland, Mäkinen was one of the original "Flying Finns". His involvement in motor vehicles started at a young age through his father, Antero, who owned a large transport company. He began rallying in 1959 with a Triumph TR3 along with his brother entering the the 1000 Lakes Rally before moving on to an Austin Healey 3000, finishing fifth in the RAC Rally in 1963, and then in 1962 getting hired by a Finnish BMC dealer to drive Minis and making his international debut at the RAC Rally that year finishing an impressive 7th. This brought him to the attention of BMC Rally Manager Stuart Turner who signed him in 1963 to drive for the works team. Driving both Mini Coopers and Austin Healey 3000, he participated in a number of international events, including making his debut at Rallye Monte-Carlo. His best result was the fifth place at RAC Rally at the wheel of Austin Healey.
He mostly drove Minis during 1964 but drove a Healey to second in the RAC Rally that year and taking his first international win at International Tulip Rallye in Netherlands.
He returned to the Mini Coopers in 1965, winning the Monte Carlo Rally and the 1000 Lakes and capturing a Coupe des Alpes at the Alpine Rally. He finished second again in the RAC Rally that year, once again aboard a Healey. He also traveled to Australia to race in the Bathurst 500. Driving a Mini Cooper S, he finished 6th overall and 3rd in class sharing the car with Paddy Hopkirk.
In 1967, Timo Mäkinen famously drove his Mini at a high speed through the famous Ouninpohja stage of the 1000 Lakes with the car's bonnet open. The leather straps holding the bonnet down having come loose. He couldn't stick his head far enough out of the side window so resorted to an almost continual sideways drift so he could see the road ahead. In doing so he set the third fastest time and won the Rally overall, for the third year in a row. He also travelled to Bathurst again and finished 7th overall and 3rd in class in with Australian driver John French.
In 1969 Mäkinen also got involved in power boat racing and won the inaugural Round Britain race in 1969 in his boat Avenger Too, powered by three V8 engines.
Mostly associated with Mini-Coopers and Big Healeys he later drove very successfully for Ford and Peugeot as well becoming one of only three men to win the RAC Rally three times in a row, the third time coming in 1975 at the wheel of a Ford Escort RS1800 (1973-1975). He also won the Finnish Rally Championship three times, the ice track championship six times and the Saloon Car Championship three times.
He continued to be active competing in Historic and Vintage Rallies, making an appearance in 1994 when Mini celebrated the 30th anniversary of their 1964 Monte Carlo win by Paddy Hopkirk.
In 2010, he was among the first four inductees into the Rally Hall of Fame, along with Carlsson, Hopkirk and Rauno Aaltonen. Timo was no relation to Tommi Makinen, who also became a famous Flying Finn, winning four World Championships driving for Mitsubishi in the 1990's.
Timo Makinen died on May 4, 2017 of natural causes.