In 1980 he finished third in the Open Spanish Championship and in 1981 he presented as fourth in the Fukuoka Marathon with 2:11:19 h a national record. In 1983 he was again third in the Open Spanish Championship and improved in seventh at the World Athletics Championships in Helsinki his national record to 2:11:05. At the Chicago Marathon, he finished sixth.
In 1984 he became Italian champion. The following year he was fourth in Chicago and remained with 2:09:57, the first Italian under the 2:10 -hour barrier.
After a 13th place at the European Athletics Championships 1986 in Stuttgart, he won in the fall of the New York City Marathon. In 1987 he was fourth at the London Marathon. After he had become 1988 VII at the Los Angeles Marathon and fifth at the Boston Marathon, he was nominated for the Olympic Games in Seoul, where he broke in on rank 19. End of the season he won the Honolulu Marathon.
In 1989 he won bronze at the IAAF World Cup Marathon in 1990 and silver at the European Championships in Split. In 1991 he finished seventh at the Turin Marathon.
Gianni Poli was supervised by the coach Gabriele Rosa. Today he lives in Toblach, where he organized Long way of the Dolomites, Cortina - Dobbiaco the Run since 2000 on his former training track, the bike path.