Born in Trondheim, Sør-Trøndelag,[4] Tønne started his career with Nardo before joining Rosenborg's youth system in 2006.[5] He was released by Rosenborg at his own request after two years at the club and subsequently joined Strindheim.[5] At Strindheim he was the team's top scorer two seasons running as a left back.[6]
Sheffield United
Tønne undertook a trial with English Championship club Sheffield United during September 2010 before signing a permanent deal in February 2011 as part of the club's development squad.[7][8][9] After impressing in the reserve team he was called up to the first team squad and eventually made his debut on 9 April 2011, coming on as an 86th minute substitute against Middlesbrough in a 2–1 home defeat.[10] He finished the 2010–11 season, his first in senior football, with two appearances as United were relegated to League One.[11]
Tønne's first goal for United came when he scored in the 79th minute against League Two side Burton Albion in the Football League Trophyfirst round on 30 August with a strike from outside the penalty area, which proved to be the winning goal in a 2–1 victory.[12] He then scored his first league goal for United a few days later with a fine volley to cap off a 4–0 victory against Bury,[13] which he described as "something special".[14] Having established himself on the fringes of the first team Tønne signed a contract extension in January 2012 to keep him at United until the summer of 2014,[15] and was subsequently loaned to Conference Premier side York City until the end of the 2011–12 season.[16] He made his debut in a 1–0 victory at home to Ebbsfleet United in the FA Trophythird round on 14 February 2012, and scored his only goal for York with the winner away at Braintree Town in a 1–0 victory on 21 April, a result that confirmed York's place in the play-offs.[17][18] He took no part in the play-offs, which York won to earn promotion to League Two, finishing his loan with four appearances and one goal.[17]
Tønne did not feature for United the following season and in March 2013 he was allowed to return to Norway for a trial with HamKam,[19] and was subsequently signed an eight-month loan deal with the club.[20] He made his debut in HamKam's opening game of the 2013 season, a 2–2 home draw with Stabæk on 6 April 2013.[3]
Sandnes Ulf
On 8 August 2013 it was confirmed that Tønne had been recalled from his loan at HamKam so that he could sign for Sandnes Ulf in the Tippeligaen on a permanent basis, thus ending his career with Sheffield United.[21]
Tønne made his debut, coming on as a 57th-minute substitute for Marius Helle against Tromsø on 11 August 2013, when his new teammates won 2–1 at home.[22]