He was elected as the Member of Provincial Parliament (MPP) for the west-end Toronto Dovercourt electoral district in 1959.
He was appointed to the Canadian Senate in 1967, forcing him to resign his provincial seat in the Legislative Assembly of Ontario.
Andrew was born in Belfast, Northern Ireland, in 1924, the fourth child of Joseph Stanley Thompson and his wife Edith Florence Magill.
He was a student at the University of Toronto from 1942 to 1943 until he joined the Royal Canadian Navy during World War II as a Sub-Lieutenant, serving aboard minesweepers.
[9] Thompson suffered a physical breakdown in late 1966 as a result of his involvement in an automobile accident in which two elderly women were seriously injured.
[7] He also had existing health problems, specifically a heart murmur, combined with exhaustion, high blood pressure and a lengthy bout of influenza.
[13] Reform Members of Parliament hired a Mariachi band and served burritos in the lobby of the Senate to draw attention to the issue.
[15] A subcommittee reported on 19 February recommending that Thompson be found in contempt and that he be suspended for the remainder of the session.
Later they found Thompson in contempt of the upper chamber for not complying with orders to return to Ottawa to explain his attendance record, resulting in the suspension of his salary and tax-free expense allowance.
[6][17] The media's exposure of Thompson's attendance and his colleagues' tolerance of it led the Senate to toughen the rules governing its members and sick leave while also increasing the financial penalties for missing too many sittings during a session.