In 1991, Wertheimer was awarded the Israel Prize for his special contribution to society and the State of Israel.
In 2008 he received the Buber-Rosenzweig-Medal.
In 1945 he joined the Palmach, where he served as a technical officer in the German Unit – a special guerilla force trained with British cooperation to participate in combat operations against the German army, should it reach Palestine. In 1947, he joined the Haganah and worked in the development and improvement of cannons. During the 1948 Arab-Israeli War, he served as a technical officer in the Yiftach Brigade.
In 1952, Wertheimer started his own Business in the backyard of his home in Nahariya, a small metal shop and tool making company called ISCAR. The company quickly became a success and attracted the interest of Discount Investments, who later became a minority investor in the company. Today, ISCAR is one of the world's largest (by sales) manufacturers of carbide industrial-cutting tools, which are used by carmakers like General Motors and Ford. ISCAR branches exist in over 50 countries worldwide and the company employs nearly 6,000 people.
In 1969, as part of Israeli efforts to overcome the French weapons embargo after the Six-Day War, Wertheimer founded ISCAR Blades which later became Blades Technology Ltd. – one of the largest manufacturers of blades and vanes for jet engines and industrial gas turbines. Today, Blades Technology's customers include Pratt & Whitney, Rolls-Royce, Snecma, General Electric, MTU Aero Engines, Techspace Aero, Solar Turbines, and others.
In 1977 Wertheimer was amongst the founding members of Democratic Movement for Change, a new centrist political party. The party was highly successful, winning 15 seats in the 1977 elections, with Wertheimer taking one of the seats. When the party split up in 1978, he joined Shinui. In 1981 following an accident, he resigned from the Knesset (was replaced by Stella Levy) and returned to his Business ventures. During his term in the Knesset, he was a member of the Economics Committee. He remains active in bridging gaps between the Jewish and Arab populations of Israel, particularly by boosting Arab participation in the country's high-tech sector.
Wertheimer's model park is the Tefen Industrial Park. Built in 1982, it encompasses everything from transportation to cultural and educational facilities. Tefen is one of four such parks in Israel that generate some $1 billion in combined revenue. Wertheimer is especially proud of the industrial park currently being constructed in the Arab-Israeli city of Nazareth, where Jews and Arabs will work side by side. "Coexistence in the industrial park in Arab Nazareth is a good Example of coexistence. When people work together, they have no time for nonsense. They're too tired at night to commit terrorist acts. They're satisfied, they engage in producing. They work together, not against each other," elaborates Wertheimer on the success of his model.
Wertheimer has four children, eleven grandchildren and two great-grandchildren (as of July 2002).
Prior to 2013 elections, he took the honorary final slot on Tzipi Livni's new list, Hatnuah. He endorsed her alliance with Labor, the Zionist Union, in 2015.
With an investment of some $22 million, the Nazareth Industrial Park comprises an 18,000-square-meter (193,750 sq. ft.) complex spread over 14 landscaped acres. With space for about 30 export-oriented firms, the park is expected to provide 500 to 1,000 jobs over the next decade and to play an active role in strengthening Nazareth’s economic base.