Nico Goldinger was born in Riga, Latvia, then part of Imperial Russia. After the Russian Revolution (1917) his family moved to the Ukraine, and then to Moscow, where he trained as a ballet dancer. He later moved to Berlin, where he read languages and history at Berlin University, and played chess rather than bridge. He moved to London in 1936, where his bridge career began. His father had been a banker, but in Germany the family became timber merchants. Nico changed his surname to Gardener after he settled in London. He became a naturalised British citizen in due course.
Gardener's partners in bridge competition included some of the great players of the day, such as Pedro Juan, Victor Mollo, Louis Tarlo, Iain MacLeod and Adam Meredith. As a tournament player he won World Mixed Teams in 1962 with Boris Schapiro, Rixi Markus and Fritzi Gordon. He won the European Championship twice out of five attempts, and competed in two Bermuda Bowls (1950 and 1962) and the 1960 Olympiad.
In domestic bridge he won the Gold Cup six times, firstly in 1946, and the Waddington Master Pairs in 1953. He won the Sunday Times Invitational Pairs in 1970 with Tony Priday; this prestigious tournament featured some of the world's strongest partnerships. He also played rubber bridge for many years at Lederer's club and at his own London School of Bridge.
Gardener was married, and became the father of Nicola Smith (born 1949), the leading British woman player of the 1975–1995 period. His wife, Pat Gardener née Hyman (c. 1920–1988), was also an international player: she played in three European women's championships.
Nico founded the London School of Bridge in 1952 in the King's Road, Chelsea, above a frock shop. There he supervised the bridge teaching and the rubber bridge rooms where beginners could practice at the game for small stakes. The teachers were some of the best players in the country, and there were about 2000 students each year. The school survived his death, but no longer exists. Another of Nico's ventures was the bridge cruise, of which he was an early promoter. Each summer would find him hosting on a Mediterranean cruise ship, conducting lessons and practice in four or five different languages, and accompanied by an attractive assistant.
One of Gardener's established partners was the outstanding and prolific bridge writer Victor Mollo, a contemporary whose family fled Russia after the 1917 revolution. Together they produced two classic books.
- Card Play Technique, or the art of being lucky, Victor Mollo and Gardener (George Newnes, 1955), 381 pp. OCLC 21982767
- Bridge for Beginners, Mollo and Gardener (Duckworth, 1956), 160 pp. OCLC 59030213; US ed. 1960, A.S. Barnes
- Master Bridge (Macmillan, 1983), 140 pp. – Macmillan in association with Channel 4. OCLC 16595486
- American Contract Bridge League. The Official Encyclopedia of Bridge (5th Edition). p. 627.
- "Nico Gardener". The Times. London, England. 16 December 1989. p. 12.
- Gardener apparently claimed 1906, but his passport and the Encyclopedia of Bridge (ACBL, New York) claim 1908.
- "Nico Gardener". Alan Hiron. Bridge Magazine. February 1990. Reprint at English Bridge Union. Retrieved 2014-06-18.
- Alan Hiron 1988 and . Article and obituary, reprinted in Hasenson P. 2004. British Bridge Almanack. 77, London. pp. 90, 188.