Netanyahu: The loser who always wins.

Netanyahu has led the Likud in 12 Knesset elections, over 33 years: More elections than any other Israeli politician, although Begin was leader of the Likud or Herut for just as long. Under Netanyahu's leadership, the Likud did not always emerge as the largest party and he did not always become prime minister. 

Ben Gurion particpated in 5 elections over 15 years, winning them all. Begin led the Likud (or its earlier version called Herut) in all 10 elections from 1948 to 1981. Over 30 years (since 1951), Begin's share of the vote either increased or remained static in every election: He never won less seats than in a previous election.

Elections	Likud seats under Begin	Labor Leader	Labor Seats
1949	14	Ben Gurion	46
1951	8	Ben Gurion	45
1955	15	Ben Gurion	40
1959	17	Ben Gurion	47
1961	17	Ben Gurion	42
1965	26	Eshkol	45
1969	26	Golda	56
1973	39	Golda	51
1977	43	Peres	32
1981	48	Peres	47

In 1982 Begin resigned and Shamir took over, leading the Likud in 3 elections (winning one). Since winning leadership of the Likud in 1992, 33 years ago, Netanyahu has contested 12 Knesset elections as head of the Likud. In 7 of those elections, Netanyahu became Prime Minister . Curiously he has won the most Knesset seats only 5 times in 12 elections, but still managed to become (or remain) Prime Minster 8 times.

Netanyahu has never lost a contest for leadership of the Likud. Sharon became leader because Netanyahu resigned in 1999, after he lost a general election to Ehud Barak.
Ariel Sharon left the Likud in 2005, creating a new party called Kadima, and Netanyahu has led the Likud ever since.

Since 1992 there have been three direct election contests for the role of Prime Minister. Netanyahu contested those twice, winning once and losing once.

In only one election in the last 28 years, was the Likud not led by Netanyahu: Ariel Sharon won the 2003 Knesset elections and accompanying direct election of the Prime Minister.

When has Netanyahu lost?

The first election Netanyahu lost was in 1999. At the time, the Prime Minister was elected directly (a bit like US presidential elections) and one voted for the parties separately. Netanyahu faced two rival candidates, both highly decorated former Generals: Yitshak Mordechai (representing a new center party) and Ehud Barak (leading the Labor party). Netanyahu lost.

The second election Netanyahu lost was in 2006.  Sharon had taken most of the Likud into a new party and then had a stroke. Ehud Olmert led Kadima (Sharon's new party) and the Likud led by Netanyahu came third, with a mere 12 seats.  Technically, Netanyahu also lost to Tzippi Livni in 2009, by a single seat: But she was unable to form a coalition and he became Prime-Minister. 

 
Why did Netanyahu not win?

Well, Netanyahu has only once won an election in which his chief rival was a former Army Chief of Staff: He lost to Barak and he has only beaten Gantz once.  He lost two elections to the leaders of Kadima before that party disintegrated and vanished from the scene: Maybe the auora of the comatose Sharon was enough to keep him down. 
Most importantly, Netanyahu's record in Knesset elections was not stellar until 2013: He was, however, very effective at forming coalitions. Until 2013, Netanyahu never led the largest party or won over 30 seats, since 2013 he has consistently won at least 30 seats and, except for once, always led the largest party.

Data sourced from Wikipedia.  From 1996 to 2003, the Prime Minister was directly elected, a system which disastrously fractured Israeli politics. The system was abandoned after that. 
 

Elections	Leader of  Likud	Knesset  Seats	Became   PM?	Largest party?	Winner or opposition
1996	Netanyahu	32	Yes	No	Peres (Labor) 34
1999	Netanyahu	19	No	No	Barak (Labor) 26
2003	Sharon	38	-	-	Mitzna (Labor) 19
2006	Netanyahu	12	No	No	Olmert (Kadima) 29
2009	Netanyahu	27	Yes	No	Livni (Kadima) 28
2013	Netanyahu	31	Yes	Yes	Lapid (Yesh Atid) 19
2015	Netanyahu	30	Yes	Yes	Herzog (Labor) 24
2019(1)	Netanyahu	35	Yes*	Tied	Gantz (Blue & White) 35
2019(2)	Netanyahu	32	A new election was called	No	Gantz (Blue & White) 33
2020	Netanyahu	36	Yes*	Yes	Gantz (Blue & White) 33
2021	Netanyahu	30	No	Yes	Lapid (Yesh Atid) 17
2022	Netanyahu	32	Yes	Yes	Lapid (Yesh Atid) 24