Bernhard Brenner was a merchant in Helsinki. He was married to Hilma Josefina (née Heinonen). The couple had one son.
Brenner was a member of Helsinki’s Nyländska Jaktklubben and was considered one of Finland’s most skilled helmsmen. He won the Sinebrychoff Trophy several times (1888-89, 1990, 1993, 1899, 1903-04) with different boats. In 1899, he also won the Rusanoff Cup with a boat named “Singoalla”. For his club, he worked as an authorized expert. He was a member of the crew of the Finnish 10 metres yacht “Nina” from Vyborg, which placed second at the 1912 Olympic Games. In a race-off for silver they beat the Russian yacht “Gallia II”.