He moved to Germany in 1983, where he was looking to replace German midfielder Paul Breitner at Bayern Munich. Here he remained for three years, winning two German Bundesliga championships. Lerby was selected for the Danish national team at the 1984 European Championship, where he played full time in Denmark's four matches, and scored a goal in the semi-final against Spain, which saw Denmark eliminated on penalty shoot-out. He also played full time in Denmark's four games at the 1986 FIFA World Cup, where he scored a goal in Denmark's 6-1 win against Uruguay.
His career continued for French team AS Monaco from 1986 to 1987. Lerby moved back to the Netherlands in 1987 and was reunited with Frank Arnesen, now at Ajax' rivals PSV Eindhoven. He was a part of the 1988 European Cup winning PSV squad, also including fellow Danes Jan Heintze and Ivan Nielsen, Frank Arnesen being out with an injury for the final against SL Benfica. He was a part of the Danish squad for the 1988 European Championship, before he ended his active career in 1989.
Between 9 October 1991 and 10 March 1992 he spent some time as coach with Bayern Munich, as successor of Jupp Heynckes. With a spell of undistinguished results, including a combined 6-3 UEFA Cup elimination by his former club B 1903, Lerby effectively ended his managerial career and became a FIFA-licensed sports agent (Essel Sport Managements). Soren Lerby had been married to Dutch singer and actress Willeke Alberti (1981-1996). Together they had a son: Kaj. Soren Lerby afterwards married for the 2nd time to Arlette van der Meulen and with her he had a second son. He now lives in the Netherlands again, in the small village of Laren.