Originally from Dallas, Texas, Newhouse attended Lake Highlands High School where he was a two-year letterman in football. He was named first-team all-district 10-5A and received Offensive Line MVP honors as a senior while also being named Lake Highlands' Most Outstanding Offensive Blocker. He also lettered in track & field in shot put, and was the 2006 UIL Texas State shot put champion. Newhouse also lettered in weightlifting, where he competed in powerlifting and earned a third-place finish in the 2005 state championships. He was also very active on campus at Lake Highlands as a member of the Horticulture Society and Japanese Club. He has one sibling, an older brother named John Newhouse.
Newhouse played college football at Texas Christian. In his first year, he was the only true freshman to play on offense and totaled 10 knockdown blocks. He made his collegiate debut in the season-opening 17-7 win at Baylor where he recorded a knockdown block in that contest. His sophomore year, he was an honorable-mention All-Mountain West Conference, after he started all 13 games at left tackle and led TCU in knockdown blocks and overall blocking grade. He was named second-team All-Mountain West Conference his junior season after he started every game at left tackle for the second straight season, running his consecutive games started streak to 26. His senior year he was first-team All-Mountain West Conference, leading him to be invited to the NFL Combine and to play in the East-West Shrine Game. He also appeared on the Rotary Lombardi Award Watch List after being ranked as the Best Offensive Lineman in the state of Texas by Dave Campbell's Texas Football. He was third-team All-American by Rivals.com and an honorable-mention All-America selection by SI.com.
Newhouse was inactive for every game in his rookie season before he was placed on injured reserve on December 31. Newhouse started at left tackle for 13 games during 2011 season when the Packers went 15-1.  Newhouse continued as the Packers' starting left tackle for all 16 regular season games and 2 playoff games in 2012.