Harold Arthur Martens was born on September 8, 1941 at Herbert, Saskatchewan to Eugene and Lydia Martens. He attended elementary school in Leonard and high school in Stewart Valley.
Prior to entering provincial politics, Martens was a rancher and farmer on the family farm in the Leinan district. He served as Councillor (1973-1975) and Reeve (1975-1979) for Saskatchewan Landing Rural Municipality No. 167. Martens was a director of the Saskatchewan Association of Rural Municipalities from 1977 to 1978. He also served as an appointee to the University of Regina Senate and the Saskatchewan Federation of Agriculture.
Martens was first elected to the Saskatchewan Legislature in 1982 and served as a Progressive Conservative MLA for the Morse constituency until 1995. He served in the Grant Devine Government as Associate Minister of Agriculture and Food (1989-1991). Martens also served as Minister Responsible for the Agricultural Credit Corporation of Saskatchewan (1989-1991), the Saskatchewan Grain Car Corporation (1989-1991), the Saskatchewan Water Corporation (1989-1991) and the Souris Basin Development Authority (1989-1991).
After the Devine Government was defeated in 1991, Martens served as Opposition Deputy Leader (1994-1995) and Opposition Finance Critic (1994-1995). He also served as Chair of the Standing Committee on Public Accounts (1991-1995).
Martens did not run in the 1995 provincial general election. He returned to the Leinan district and resumed ranching full-time, and later resided in Swift Current. He was Reeve of Excelsior Rural Municipality No. 166, and was the chair of the constituency board for the Conservative Party of Canada for the Cypress Hills-Grasslands riding and a board member for the Saskatchewan Party in the Swift Current constituency.
Martens received the Queen's Silver Jubilee Medal in 1978 for his outstanding service to the community and a Saskatchewan Centennial Medal in 2005 in recognition of his community involvement in the province.
Martens married Sylvia Schroeder on August 21, 1966. They had three children: Tony, Chad and Joe.
Martens died at Swift Current on January 8, 2023.