[1] Lammer was born on 25 March 1982 to parents Ernst and Susi, and started playing tennis at the age of six.

In 2009 in Gstaad, Lammer won his first ATP tour title with fellow Swiss player Marco Chiudinelli.

[1] Lammer represented Switzerland in the 2014 Davis Cup World Group 1R, partnering with Marco Chiudinelli to win 3–2 over Serbia.

Lammer retired in March 2015, after playing a doubles match with Roger Federer in Indian Wells.

Lammer cites Stefan Edberg, Pete Sampras and Roger Federer as his tennis idols.