Holmquist first helped the Swedish dance band Curt Haagers in 1966. He played the organ in the band until he left in 1969. He conducted the Swedish entry, "Diggi-loo Diggi-ley", in the 1984 Eurovision Song Contest and performed by the Herreys it won the contest. Holmquist conducted the Swedish entries for the Eurovision Song Contest on six occasions: 1984, 1985, 1987, 1990, 1993 and 1997. In addition to conducting the Swedish entries he also conducted the Belgian entry in 1985.