|Full name||Josef Alexander Martínez Mencia|
|Date of birth||19 May 1993|
|Place of birth||Valencia, Venezuela|
|Height||1.70 m (5 ft 7 in)|
|2013–2014||→ Thun (loan)||18||(8)|
|2017||→ Atlanta United (loan)||3||(5)|
|* Senior club appearances and goals counted for the domestic league only and correct as of 01:50, 18 June 2017 (UTC).
‡ National team caps and goals correct as of 01:33, 24 March 2017 (UTC)
He began his career with Caracas. In 2012, he was acquired by Swiss Super League club Young Boys, before spending a year on loan at Thun. In 2014, he was sold to Italian club Torino, and in 2017, Major League Soccer expansion side, Atlanta United FC.
Martínez made his debut for Caracas on 21 August 2010 against Estudiantes de Mérida, entering as a substitute in the 70th minute, won 1–0. He scored his first goal in a 2–2 draw against Deportivo Petare on 21 November 2010.
BSC Young Boys
On 3 January 2012 Caracas announced Martínez had been sold to BSC Young Boys in the Swiss Super League for a period of four years with fellow right-back Alexander Gonzalez. He debuted on 5 February 2012 against Servette FC, which the Young Boys won 3–1. After a string of good performances, Martínez was called up to the Venezuela national team, as well as awarded his first start for Young Boys on 21 October 2012, in which he scored his first goal for the Swiss club with a volley in the 50th minute against Grasshopper Club Zürich.
After one season in the Swiss capital city, he was sent on loan to Thun. After scoring 8 goals in 18 games with the team from Bernese Oberland, he was momentarily the top scorer in the Swiss Super League and recalled by Young Boys.
On 7 June 2014, he was sold to Italian Serie A club Torino for a reported fee of €3 million. He made his debut in the third round of the 2014–15 Europa League, won 3–0 against Sweden's Brommapojkarna. He scored his first goal for the Granata in the return leg, won 4–0 in Turin (7–0 on agg.).
He made his league debut on 14 September in a 2–0 loss away to Sampdoria. On 7 December, he scored his first goal in Serie A during a 2–2 draw with Palermo. Four days later, he scored his first brace in the Europa League against Copenhagen, which ended 1–5 in favour of Torino.
Atlanta United FC
On 2 February 2017, he was loaned with a buying option to Major League Soccer expansion team Atlanta United. He made his league debut on 5 March in a 1–2 home defeat against New York Red Bulls. He scored his first career hat-trick, and the first hat-trick in the history of the club, in a 6–1 win away to Minnesota United FC.
On 21 March, Atlanta announced they had activated the buyout clause for an undisclosed transfer fee. He was named the MLS Player of the Month for March after scoring five goals in his first three games in the league. 
On 10 November 2016 (matchday 11 of the 2018 FIFA World Cup qualification), Martínez scored a hat-trick against Bolivia in a 5–0 win in Maturín.
- As of 6 April 2017
|Venezuela national team|
|1.||22 May 2013||Metropolitano de Mérida, Mérida, Venezuela||El Salvador||2–1||2–1||Friendly|
|2.||14 August 2013||Pueblo Nuevo, San Cristóbal, Venezuela||Bolivia||1–0||2–2||Friendly|
|3.||31 March 2015||Lockhart Stadium, Fort Lauderdale, United States||Peru||1–0||1–0||Friendly|
|4.||17 November 2015||Polideportivo Cachamay, Puerto Ordaz, Venezuela||Ecuador||1–3||1–3||2018 FIFA World Cup qualification|
|5.||5 June 2016||Soldier Field, Chicago, United States||Jamaica||1–0||1–0||Copa América Centenario|
|6.||6 September 2016||Metropolitano de Mérida, Mérida, Venezuela||Argentina||2–0||2–2||2018 FIFA World Cup qualification|
|7.||10 November 2016||Estadio Monumental de Maturín, Maturín, Venezuela||Bolivia||2–0||5–0||2018 FIFA World Cup qualification|
- "Venezuela - J. Martínez - Profile with news, career statistics and history - Soccerway". Uk.soccerway.com. Retrieved 2012-05-24.
- "Martinez al Toro". TORINO FC 1906 OFFICIAL WEBPAGE. Retrieved 2014-06-07.
- "BROMMAPOJKARNA VS. TORINO 0 - 3". soccerway.com. Retrieved 2 August 2014.
- "TORINO VS. BROMMAPOJKARNA 4 - 0". soccerway.com. Retrieved 8 August 2014.
- Martinez all'Atlanta torinofc.it
- Atlanta United Acquire Josef Martínez as Designated Player atlutd.com
- "Atlanta United’s Martinez honored by MLS". The Atlanta Journal-Constitution. Retrieved April 6, 2017.