Lingenfelter was born on February 27, 1949, in Shaunavon. He studied at the University of Saskatchewan, where he earned a political science degree. He operated his own farm near Shaunavon and briefly worked for Canada Customs. Lingenfelter was elected MLA for Shaunavon in 1978, and re-elected in 1982. He served as Minister of Social Services in the Allan Blakeney government from 1980 to 1982. He survived the Progressive Conservative landslide in 1982, and from 1982 to 1986 was Opposition House Leader, but was defeated in 1986. He was elected president of the Saskatchewan New Democratic Party in 1987 and won the Regina Elphinstone seat vacated by Allan Blakeney in 1988. Lingenfelter became Opposition House Leader and Opposition critic for Privatization and Saskatchewan Government Insurance. In 1991, Lingenfelter was re-elected. He was appointed Minister of Economic Diversification and Trade in the eleven-member “war Cabinet” of the newly formed NDP government. He also became government House Leader. He felt that economic growth required a collaborative effort between the public and private sectors of the economy. In 1995, Lingenfelter became Deputy Premier, and was appointed Minister of the Crown Investments Corporation in 1997. The 1999 provincial election cost the NDP nearly all of its rural seats. Due to his farming background, Lingenfelter was appointed Minister of Agriculture and Food in 1999 but resigned in 2000. He moved to Calgary as vice-president of government relations for Nexen, an international oil and gas company.