Northey was born in Mahanoy City, Pennsylvania; he batted left-handed, threw right-handed, stood 5 ft 10 in (1.78 m) tall and weighed 195 lb (88 kg) during his playing career.

Northey graduated from Frackville High School and went to Duke University.

In 12 MLB seasons, he played in 1,084 games and had 3,172 at bats, with 385 runs scored, 874 hits, 172 doubles, 28 triples, 108 home runs, 513 runs batted in, seven stolen bases, 361 walks, a .276 batting average, .352 on-base percentage, .450 slugging percentage, 1,426 total bases and 14 sacrifice hits.

[1] In 1956, as a member of the White Sox, he batted .385 and collected 15 pinch hits, with three homers and 21 RBI.

Northey was a coach on the staff of skipper Danny Murtaugh, his former teammate on the early 1940s Phillies, with the Pittsburgh Pirates from 1961 to 1963.