The son of John Wesley Leavens and Elizabeth Haycroft, he was born in Owen Sound, Ontario.
[1][2] Bertram married Myrtle May Leavens (nee Webb) on September 11, 1911 in Owen Sound, Ontario.
They had 3 sons (William John (1912-1982), Bertram Elijah (1918-1918) and Charles Wesley (1920-1976)) and a daughter (Eva Lorraine (1914-1974)).
Leavens ran unsuccessfully for the Greenwood seat in the Canadian House of Commons in 1935 and 1940 as a CCF candidate, losing both times to Denton Massey.
[3] In the 1943 provincial election, he ran as a CCF candidate in the downtown Toronto riding of Woodbine.